last updated at 2017-03-24 12:25:00

LJCR | 4451 |

Jan de Heer and Steve Muir | 2864 |

Colin Barker | 321 |

Michael Dambmann | 251 |

Tommaso Tanto | 147 |

Terenzio Lazzarotto | 144 |

Pio Leonardi | 99 |

Flavio Perona | 91 |

Anastasios Tampakis | 89 |

Enzo Franzese | 77 |

Kamal Fadlaoui | 74 |

Jan de Heer | 47 |

Alessandro Jurcovich | 37 |

Rade Belic and Dragan Stojiljkovic | 35 |

Rade Belic | 34 |

Mathias Liesener | 34 |

Barnabas Toth | 28 |

Gerald Unger | 27 |

Kinski and Genivaldo Pereira | 26 |

Dietmar Pree | 24 |

Andrei Ochmat | 23 |

Vinicius Alves | 22 |

Chaoying Dai, Ben Li and Michel Toulouse | 22 |

Marco Meoli | 20 |

Felix Rodriguez Martin | 20 |

Luciano Rezende | 18 |

Rade Belic and Jan de Heer | 13 |

Adolf Muehl | 13 |

Sveta Marjanovic | 9 |

Aline Marie Menezes Wanderlei | 8 |

Karsten Schölzel | 6 |

W.h.mills and R.c.mullin | 5 |

Roy Gourgi | 5 |

W.h.mills | 4 |

Sveta Marjanovic and Anastasios Tampakis | 4 |

Jan de Heer and Rade Belic | 4 |

Daryl Burns | 4 |

Weberazevedo | 2 |

Sveta Marjanovicandanastasios Tampakis | 2 |

Steve Muir | 2 |

Mario Pina | 2 |

Kleszek | 2 |

Iliya Bluskov | 2 |

Guenther Schlegl | 2 |

Francisco Carlos | 2 |

Claus Friis | 2 |

Bluskov and Hamalainen | 2 |

W. H. Mills | 1 |

Tung Le | 1 |

Riccardo Bertolo and Jan de Heer | 1 |

Riccardo Bertolo and Francesco Santisi | 1 |

Rade Belic and Dietmar Pree | 1 |

Nino Aspesi - Alessandro Jurcovich | 1 |

Namyk Kemal Erdogan | 1 |

Kinsky and Genivaldo Pereira | 1 |

Karsten Scholzel | 1 |

Jose Milan Vega | 1 |

Jaera | 1 |

Igor Lazebnik | 1 |

Fausto Peirano | 1 |

Dietmar Pree and Rade Belic | 1 |

Dietmar Pree and Adolf Muehl | 1 |

Daniel Morais | 1 |

Chaoying Dai, Ben Li and Michel Toulouse, Reduced By Rade Belic | 1 |

Alexandre Spaeth | 1 |

Alessandro Jurcovich E Marco Meoli | 1 |

Adolf Muehl and Dietmar Pree | 1 |

A. Tampakis and A. Jurchovich | 1 |

A. Betten, R. Laue and A. Wassermann | 1 |

Overall there have been 65484 entries from 123 different contributors

LJCR | 45851 |

Jan de Heer and Steve Muir | 4988 |

Michael Dambmann | 2239 |

Tommaso Tanto | 1733 |

JCD Article | 1632 |

Flavio Perona | 1498 |

Rade Belic | 1441 |

Terenzio Lazzarotto | 1382 |

Rade Belic and Dragan Stojiljkovic | 539 |

Colin Barker | 457 |

Gerald Unger | 343 |

Kinski and Genivaldo Pereira | 278 |

Anastasios Tampakis | 257 |

Felix Rodriguez Martin | 244 |

Enzo Franzese | 228 |

Barnabas Toth | 228 |

Pio Leonardi | 194 |

Dietmar Pree | 155 |

Alessandro Jurcovich | 144 |

Steve Muir | 131 |

Aline Marie Menezes Wanderlei | 131 |

Jan de Heer | 129 |

Francisco Carlos | 127 |

Marco Meoli | 107 |

Luciano Rezende | 100 |

Kamal Fadlaoui | 89 |

Vinicius Alves | 86 |

Sveta Marjanovic | 68 |

Nino Aspesi | 49 |

Mathias Liesener | 47 |

Dietmar Pree and Rade Belic | 41 |

Jose Milan Vega | 40 |

Chaoying Dai, Ben Li and Michel Toulouse | 39 |

Rade Belic and Jan de Heer | 38 |

Jaera | 38 |

Fausto Peirano | 37 |

Gino Grazin and Rade Belic | 31 |

Andrei Ochmat | 31 |

Dragan Stojiljkovic | 27 |

Jan de Heer and Rade Belic | 19 |

Stefano de Martino | 14 |

Roy Gourgi | 14 |

Kleszek | 12 |

Kabila | 11 |

Flavio.perona | 11 |

Igor Lazebnik | 10 |

Weberazevedo | 8 |

Sildemar Castro | 8 |

Alessandro Jurcovich E Marco Meoli | 8 |

Adolf Muehl | 8 |

Weber Azevedo | 7 |

Riccardo Bertolo | 7 |

Daryl Burns | 7 |

Mario Pina | 6 |

Karsten Schölzel | 6 |

W.h.mills and R.c.mullin | 5 |

Sveta Marjanovic and Anastasios Tampakis | 5 |

W.h.mills | 4 |

Sveta Marjanovicandanastasios Tampakis | 4 |

Riccardo Bertolo and Francesco Santisi | 4 |

Rade Belic and Dietmar Pree | 4 |

Leopio | 4 |

Ivan Baptiste and Rade Belic | 4 |

Michael Damb | 3 |

Marco Meoli E Alessandro Jurcovich | 3 |

Claus Friis | 3 |

Tarullig / Aspesi | 2 |

Riccardo Bertolo and Jan de Heer | 2 |

Ricardo Ramalho | 2 |

Paolo Ferlaino | 2 |

Meoli Marco | 2 |

Karsten Scholzel | 2 |

Iliya Bluskov | 2 |

Genivaldo Pereira | 2 |

Bluskov and Hamalainen | 2 |

Alessandro Jurcovich E Stefano de Martino | 2 |

Adolf Muehl and Dietmar Pree | 2 |

W. H. Mills | 1 |

Tung Le | 1 |

Tarullig/aspesi | 1 |

Steve Muir, Improving One By Jan de Heer | 1 |

Simple Construction: Doubled (50,9,3) and Deleted An Element | 1 |

Simple Construction: Doubled (50,8,3) and Deleted An Element | 1 |

Simple Construction: Doubled (50,8,2) and Deleted An Element | 1 |

Simple Construction: Doubled (50,6,2) and Deleted An Element | 1 |

Simple Construction: Doubled (50,11,3) and Deleted An Element | 1 |

Simple Construction: Doubled (50,11,2) and Deleted An Element | 1 |

Simple Construction: Doubled (50,10,4) and Deleted An Element | 1 |

Simple Construction: Doubled (50,10,3) and Deleted An Element | 1 |

Simple Construction: Doubled (50,10,2) and Deleted An Element | 1 |

Quadrupling Construction | 1 |

Qlatino | 1 |

Peter Rosendahl | 1 |

Paramini and Kabila and Aspesi | 1 |

Nino Aspesi - Moreno Paramini | 1 |

Nino Aspesi - Alessandro Jurcovich | 1 |

Namyk Kemal Erdogan | 1 |

Marjanovic Jurcovich Aspesi | 1 |

Mario Tessuto | 1 |

Marco Meoli Sveta Marjanovic | 1 |

Marco Meoli Alessandro Jurcovich | 1 |

Leo Pio | 1 |

Lazzarotto Terenzio | 1 |

Kinsky and Genivaldo Pereira | 1 |

Jose Maria Milan | 1 |

Jiang Yong Ming | 1 |

Jan de Heer With Ininuga By Uros Boltin | 1 |

Grzesiek | 1 |

Gerasorte Online | 1 |

Fernando Villanova | 1 |

Edi8 | 1 |

Daniel Morais | 1 |

Chaoying Dai, Ben Li and Michel Toulouse, Reduced By Rade Belic | 1 |

Aspesi - Paramini - Tosi | 1 |

Aspesi - Paramini - Marjanovic | 1 |

Altopalato Bellariva | 1 |

Alexandre Spaeth | 1 |

Alessandro Jurcovich-sveta Marjanovic-marco Meoli | 1 |

Alessandro Jurcovich - Nino Aspesi | 1 |

Adolf Muehl and Rade Belic And Dietmar Pree | 1 |

A. Tampakis and A. Jurchovich | 1 |

A. Betten, R. Laue and A. Wassermann | 1 |

42066 | 1 |

Private tools | 2568 |

Dynamic programming construction | 1969 |

unknown | 1272 |

Simple construction | 952 |

Multiple | 628 |

Lex covering | 258 |

Constructed | 223 |

Simulated annealing | 194 |

Dynamic programming covering | 135 |

Simple construction: combined | 79 |

Simple construction: multiple | 70 |

Simple construction: induced | 67 |

Lexicographic greedy covering | 57 |

Wheel generator | 47 |

Dynamic construction | 40 |

Dynamic programming | 37 |

Simple construction: deleted element | 31 |

Tabu search | 28 |

Private tool | 28 |

Random greedy covering | 23 |

Cyclic covering | 23 |

Cyclic covering found by search program | 20 |

Simple construction: added element to c(v-1,k-1,t) covering | 18 |

Steiner quadruple system | 16 |

Simple optimization | 16 |

Sidorenko construction | 15 |

Simple combine | 11 |

Constructed using simulated annealing | 11 |

Design is based on c (v - 1, k, t) = b - v | 10 |

Cyclic construction | 10 |

Simulated annealing covering | 9 |

See paper by jrj abel et al. in discrete mathematics 307 (2007) | 9 |

Cyclic covering found by a search program | 9 |

Nurmela and ostergard simulated annealing cover | 8 |

Nurmela-ostergard symmetric covering | 7 |

Affine geometry covering | 7 |

Induced | 6 |

Exhaustive search | 6 |

Covering provided by rade belic | 6 |

Steiner triple system | 5 |

Sidorenko method | 5 |

See jct series a 49, 308-322 (1988) | 5 |

Extraction/remainder | 5 |

Colex greedy covering | 5 |

Simple construction: added element to c(v,k-1,t) covering | 4 |

See journal | 4 |

Nurmela-ostergard simulated annealing covering design | 4 |

Hanani construction (see canadian journal | 4 |

Cyclic symmetry | 4 |

Constructed using difference families | 4 |

Wheel generator, based on jan de heer and steve muir work | 3 |

Using ininuga, by uros boltin | 3 |

Steiner system | 3 |

Reverse engineering smaller systems | 3 |

Projective plane | 3 |

Modified cover32 routine by dietmar pree | 3 |

Mills, jcta 13 (1972) pp. 55-78. | 3 |

Mills, ars combinatoria, 8 (1979) pg. 247 | 3 |

Mills, ars combinatoria, 8 (1979) pg. 231 | 3 |

Mills, ars combinatoria 8 (1979) pp. 199-315 | 3 |

Found by a hill-climbing program | 3 |

Cyclic steiner system | 3 |

Covering provided by alex sidorenko (personal communication) | 3 |

Covering found by a hill-climbing program | 3 |

Constructed using dynamic programming | 3 |

Using wheel generator | 2 |

Steiner system (derived) | 2 |

Simple method construction | 2 |

Several methods (including sa) | 2 |

Nurmela-ostergard simulated annealing covering | 2 |

Jcd 1998, pp. 21-41 | 2 |

Hill-climb on cyclic orbits | 2 |

Hill-climb on affine orbits | 2 |

Covering provided by john cock (personal communication) | 2 |

Covering provided by dietmar pree | 2 |

Covering pairs by quads: mills, jcta 15:138-166, 1973. | 2 |

Constructed using difference sets | 2 |

Constructed by simulated annealing | 2 |

Communicated by d. todorov, using pg(2,4) | 2 |

Communicated by d. todorov, using pg(2,3) | 2 |

Affine plane | 2 |

Using td(6,16) and 6*modified c(18,6,2,2) | 1 |

Using td(6,15) and 6*modified c(18,6,2,2) | 1 |

Using resolvable c(72,4,2), see lamken, mullen and rees (jcd, 1997-1) | 1 |

Using resolvable c(68,4,2), see lamken, mullen and rees (jcd, 1997-1) | 1 |

Using rc(60,3,2) by lamken and mills (1993) | 1 |

Using rc(54,3,2) | 1 |

Using rc(45,3,2) | 1 |

Using dietmar pree version | 1 |

Using a resolvable c(54,6,2,2) | 1 |

Using a 4−gdd | 1 |

Using a (v,4,22*)-pbd and c(22,4,2) | 1 |

Unusual methods | 1 |

Tripling a resolvable c(25,5,2) | 1 |

Td(7,13) and 7 * modified c(15,7,2) | 1 |

Td(4,24) + 4*c(27,4,2) | 1 |

Td(4,24) + 4 * c(26,4,2) | 1 |

Td(4,23) + 4 * c(25,4,2) | 1 |

Td(4,19) & 4 * c(21,4,2) | 1 |

Td(4,18) + 4 * c(21,4,2) | 1 |

Td(4,15) and 4 * modified c(18,4,2) | 1 |

Td(4,12) & 4 * c(15,4,2) | 1 |

Superfluous-element hill climb on a random greedy covering | 1 |

Superfluous-element hill climb on a covering | 1 |

Steiner system, taken | 1 |

Simple multiple | 1 |

Simple construction: doubled (50,8,3) and deleted an element | 1 |

Simple construction: doubled (50,8,2) and deleted an element | 1 |

Simple construction: doubled (50,11,2) and deleted an element | 1 |

Simple construction: doubled (50,10,4) and deleted an element | 1 |

Simple construction: doubled (50,10,2) and deleted an element | 1 |

Simple construction: | 1 |

See w h mills in congressus numerantium 10 (1974) pp563-581 | 1 |

See paper in journal | 1 |

See j comb des , vol. 15, no. 6, pp. 511-533, 2007 | 1 |

See designs, codes and cryptography 17 (1999), 181-186 | 1 |

Reverse engineering | 1 |

Replicate 4 columns | 1 |

Quadrupling construction | 1 |

Produced with covermaster (by john rawson), wheelgenerator (by anastasios tampakis) and private tools. | 1 |

Private tools - assisted by wheel generator | 1 |

Privat tools | 1 |

Pritave tools | 1 |

Normal methods | 1 |

Mills, ars combinatoria, 8 (1979) pg. 270 | 1 |

Mills, ars combinatoria, 8 (1979) pg. 254 | 1 |

Mill, jcta 15 (1973) 138-166 | 1 |

Method | 1 |

Marco meoli | 1 |

Ininuga (by uros boltin) | 1 |

Induced annealing | 1 |

Group theory | 1 |

From td(9,9) and 9*c(14,9,2,2,3) with 5 holes | 1 |

From td(7,12) and 7*c(15,7,2,2,6) with 3 holes | 1 |

From td(7,12) and 7*c(13,7,2,2,5) with 2 holes | 1 |

From 57,8,2 | 1 |

From 1-flat on 42 numbers | 1 |

Extraction | 1 |

Ex 948 | 1 |

Ex 831 | 1 |

Ex 8 | 1 |

Ex 62 | 1 |

Ex 54 | 1 |

Ex 28 | 1 |

Ex 1821 | 1 |

Ex 16 | 1 |

Ex 15 | 1 |

Ex 1491 | 1 |

Ex 13 | 1 |

Ex 1257 | 1 |

Doubling resolvable c(25,5,2) | 1 |

Doubling c(42,4,3) | 1 |

Doubling c(36,4,3) | 1 |

Doubling c(30,4,3) | 1 |

Doubling c(18,4,3) | 1 |

Cyclic symmetrical | 1 |

Cyclic covering on z5*z7 | 1 |

Cyclic covering on z3*z17 with one point at infinity | 1 |

Cyclic | 1 |

Covering provided by konstantin katskov, found by exhaustive search | 1 |

Covering produced by floyd l. oats, using a ranking and reduction process | 1 |

Covering pairs by quints, mullin, jcmcc 2:133-146, 1987 | 1 |

Covering pairs by quints, mills & mullin, jcta 49:308-322, 1988 | 1 |

Covering found by rade belic | 1 |

Covering found by john rawson | 1 |

Covering | 1 |

Construction combined | 1 |

Communicated by d. todorov | 1 |

Combinado | 1 |

Chain rule (64,32,6)x(32,24,6) | 1 |

Block-array construction (gordon, patashnik, petro and taylor) | 1 |

Block covering | 1 |

Based on work by chaoying dai, ben li and michel toulouse | 1 |

Based on an improvement by dietmar pree | 1 |