A280809 Number of nX7 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.

0, 1047, 24490, 133067, 521862, 1736603, 5219491, 14672850, 39446188, 102668319, 261032587, 651872767, 1605291205, 3909190755, 9432062891, 22579858190, 53688882185, 126896063565, 298328702932, 698005209403, 1626059718118

Offset

1,2

Comments

Column 7 of A280810.

Links

R. H. Hardin, Table of n, a(n) for n = 1..151

Formula

Empirical: a(n) = 13*a(n-1) -72*a(n-2) +220*a(n-3) -400*a(n-4) +432*a(n-5) -256*a(n-6) +64*a(n-7) +6*a(n-8) -54*a(n-9) +183*a(n-10) -249*a(n-11) -51*a(n-12) +573*a(n-13) -672*a(n-14) +264*a(n-15) +33*a(n-16) +39*a(n-17) -156*a(n-18) +12*a(n-19) +225*a(n-20) -57*a(n-21) -390*a(n-22) +402*a(n-23) -19*a(n-24) -173*a(n-25) +66*a(n-26) +126*a(n-27) -156*a(n-28) +33*a(n-30) +93*a(n-31) -96*a(n-32) +2*a(n-33) +43*a(n-34) -45*a(n-35) -20*a(n-36) +74*a(n-37) -30*a(n-38) -18*a(n-39) +15*a(n-40) -3*a(n-41) -9*a(n-42) +15*a(n-43) -3*a(n-44) -3*a(n-45) -a(n-48) +a(n-49) for n>60

Example

Some solutions for n=4
..0..1..0..0..1..0..1. .0..1..0..0..1..1..0. .0..0..1..0..0..1..0
..1..1..1..0..1..0..1. .0..1..0..1..0..1..1. .1..1..0..1..0..1..0
..0..0..1..0..1..0..1. .1..0..0..1..0..0..0. .0..1..0..1..0..1..0
..1..1..0..1..0..0..1. .1..1..1..0..1..1..0. .1..1..0..1..0..1..1

Crossrefs

Cf. A280810.

Sequence in context: A226114 A249653 A056092 * A252307 A236273 A251375

Adjacent sequences: A280806 A280807 A280808 * A280810 A280811 A280812

Keyword

nonn

Author

R. H. Hardin, Jan 08 2017

Status

approved