A269216 Number of 3Xn 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three exactly once.

0, 1152, 18048, 308544, 4744704, 70371048, 1012764384, 14272781904, 197924795136, 2710127012280, 36731155605600, 493646491209600, 6587572246924800, 87381895621488648, 1153101183028855008

Offset: 1

Author

R. H. Hardin, Feb 20 2016

Keywords

• nonn

Comments

Row 3 of A269214.

Examples

			Some solutions for n=3
..2..3..1. .0..2..3. .0..0..0. .1..3..1. .2..2..2. .3..2..2. .0..1..0
..3..1..1. .0..0..2. .2..2..3. .3..3..1. .1..0..0. .0..0..0. .1..0..2
..0..1..3. .0..0..2. .2..2..0. .2..1..1. .0..0..2. .0..1..0. .0..0..2
		

Links

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

Crossrefs

Cf. A269214.

Formula

Empirical: a(n) = 24*a(n-1) -130*a(n-2) -248*a(n-3) +935*a(n-4) +272*a(n-5) -1768*a(n-6) +960*a(n-7) -144*a(n-8)