A268907 Number of 4Xn 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

0, 1344, 12960, 118584, 1004184, 8250912, 66210264, 522241560, 4063962024, 31282792704, 238663638432, 1807307152056, 13599932970888, 101786388133320, 758232651966984, 5625079743143376, 41579318178922608, 306353541215271960

Offset: 1

Author

R. H. Hardin, Feb 15 2016

Keywords

• nonn

Comments

Row 4 of A268904.

Examples

			Some solutions for n=4
..0..1..0..0. .0..0..0..1. .2..1..0..1. .1..0..0..0. .1..1..2..2
..0..1..0..0. .0..0..0..1. .2..1..2..2. .1..0..1..0. .2..2..1..0
..2..1..2..1. .0..0..0..1. .1..2..2..2. .0..0..1..2. .1..0..1..0
..0..1..2..1. .1..0..2..2. .2..2..1..2. .0..0..2..2. .0..0..0..1
		

Links

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

Crossrefs

Cf. A268904.

Formula

Empirical: a(n) = 18*a(n-1) -111*a(n-2) +282*a(n-3) -333*a(n-4) +180*a(n-5) -36*a(n-6) for n>12