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 A280810 T(n,k)=Number of nXk 0..1 arrays with no element equal to more than two of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 8
 0, 0, 0, 0, 1, 0, 0, 3, 3, 0, 0, 18, 56, 18, 0, 0, 72, 332, 332, 72, 0, 0, 284, 1578, 2146, 1578, 284, 0, 0, 1047, 6540, 9715, 9715, 6540, 1047, 0, 0, 3722, 24490, 37644, 41931, 37644, 24490, 3722, 0, 0, 12816, 86010, 133067, 155560, 155560, 133067, 86010, 12816, 0, 0 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,8 COMMENTS Table starts .0.....0......0.......0........0........0.........0.........0.........0 .0.....1......3......18.......72......284......1047......3722.....12816 .0.....3.....56.....332.....1578.....6540.....24490.....86010....288426 .0....18....332....2146.....9715....37644....133067....440282...1387898 .0....72...1578....9715....41931...155560....521862...1635481...4878157 .0...284...6540...37644...155560...547197...1736603...5150299..14554327 .0..1047..24490..133067...521862..1736603...5219491..14672850..39446188 .0..3722..86010..440282..1635481..5150299..14672850..39260363.100719254 .0.12816.288426.1387898..4878157.14554327..39446188.100719254.247768745 .0.43077.933792.4213683.14014639.39708623.102668319.251288174.594591866 LINKS R. H. Hardin, Table of n, a(n) for n = 1..264 FORMULA Empirical for column k: k=1: a(n) = a(n-1) k=2: [order 18] k=3: [order 18] for n>24 k=4: [order 28] for n>36 k=5: [order 37] for n>46 k=6: [order 43] for n>53 k=7: [order 49] for n>60 EXAMPLE Some solutions for n=4 k=4 ..0..1..1..1. .0..1..0..0. .0..1..1..0. .0..1..0..0. .0..1..1..0 ..0..1..0..1. .0..1..0..1. .0..0..0..1. .1..1..1..0. .1..0..0..1 ..1..0..1..0. .1..0..0..0. .1..0..1..0. .0..0..0..1. .0..1..1..1 ..1..0..1..1. .1..1..1..1. .1..1..0..0. .1..1..0..0. .0..0..1..0 CROSSREFS Sequence in context: A199237 A309651 A305541 * A283386 A278385 A245626 Adjacent sequences: A280807 A280808 A280809 * A280811 A280812 A280813 KEYWORD nonn,tabl AUTHOR R. H. Hardin, Jan 08 2017 STATUS approved

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Last modified April 12 07:56 EDT 2024. Contains 371626 sequences. (Running on oeis4.)