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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 January 25 12:40 EST 2022. Contains 350572 sequences. (Running on oeis4.)