A281569 Number of 7Xn 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 1508, 62882, 162919, 430995, 919632, 1818257, 3326246, 5744641, 9601436, 15859355, 26033851, 42510000, 69365630, 113056482, 183794484, 298249938, 483393766, 782278654, 1263834968, 2038915696, 3284498896, 5282364942

Offset

1,2

Comments

Row 7 of A281563.

Links

R. H. Hardin, Table of n, a(n) for n = 1..150

Formula

Empirical: a(n) = 6*a(n-1) -15*a(n-2) +23*a(n-3) -30*a(n-4) +36*a(n-5) -34*a(n-6) +30*a(n-7) -36*a(n-8) +43*a(n-9) -42*a(n-10) +42*a(n-11) -40*a(n-12) +27*a(n-13) -18*a(n-14) +21*a(n-15) -21*a(n-16) +15*a(n-17) -12*a(n-18) +9*a(n-19) -3*a(n-20) +a(n-21) -3*a(n-22) +3*a(n-23) -a(n-24) for n>46

Example

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

Crossrefs

Cf. A281563.

Sequence in context: A096021 A190032 A237319 * A252553 A237725 A200915

Adjacent sequences: A281566 A281567 A281568 * A281570 A281571 A281572

Keyword

nonn

Author

R. H. Hardin, Jan 24 2017

Status

approved