A268903 Number of nX7 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

576, 34344, 1585800, 66210264, 2611960344, 99308573208, 3679171151832, 133712637011640, 4788143315276472, 169455769674019992, 5940079034652505944, 206577531186380751096, 7136252899974195705720, 245118805391945325271896

Offset: 1

Author

R. H. Hardin, Feb 15 2016

Keywords

• nonn

Comments

Column 7 of A268904.

Examples

			Some solutions for n=2
..0..1..0..0..0..0..1. .1..0..1..0..0..0..1. .0..0..0..1..2..2..1
..2..2..1..0..1..2..1. .1..0..0..0..0..2..2. .1..1..2..2..1..2..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A268904.

Formula

Empirical: a(n) = 84*a(n-1) -2466*a(n-2) +31428*a(n-3) -206469*a(n-4) +750384*a(n-5) -1513404*a(n-6) +1574640*a(n-7) -656100*a(n-8)