A268771 Number of nX5 0..2 arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

96, 248, 1524, 10340, 64112, 387146, 2258084, 12951796, 73011192, 406925194, 2244513800, 12281806624, 66734787464, 360505595710, 1937557458852, 10367717536488, 55261185262316, 293537189567482, 1554428843176696

Offset: 1

Author

R. H. Hardin, Feb 13 2016

Keywords

• nonn

Comments

Column 5 of A268774.

Examples

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

Links

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

Crossrefs

Cf. A268774.

Formula

Empirical: a(n) = 4*a(n-1) +28*a(n-2) -62*a(n-3) -314*a(n-4) +78*a(n-5) +867*a(n-6) +6*a(n-7) -859*a(n-8) +46*a(n-9) +215*a(n-10) -8*a(n-11) -16*a(n-12) for n>14