A269055 Number of 4Xn 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once.

81, 666, 3258, 24192, 149358, 971844, 6053094, 37741920, 231943614, 1417576284, 8599619586, 51899214960, 311654917170, 1863739501308, 11103704855298, 65935768579488, 390381077316294, 2305171593612444, 13579182450069246

Offset: 1

Author

R. H. Hardin, Feb 18 2016

Keywords

• nonn

Comments

Row 4 of A269052.

Examples

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

Links

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

Crossrefs

Cf. A269052.

Formula

Empirical: a(n) = 6*a(n-1) +23*a(n-2) -102*a(n-3) -288*a(n-4) +250*a(n-5) +787*a(n-6) -238*a(n-7) -741*a(n-8) +124*a(n-9) +196*a(n-10) -16*a(n-11) -16*a(n-12) for n>14