A269138 Number of nX3 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three no more than once.

60, 1164, 18556, 275796, 3924212, 54199284, 732561916, 9740150372, 127846717716, 1660741102212, 21389485726684, 273519303765844, 3476418550368820, 43954347343683220, 553215363420258236, 6935081471870462788

Offset: 1

Author

R. H. Hardin, Feb 20 2016

Keywords

• nonn

Comments

Column 3 of A269143.

Examples

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

Links

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

Crossrefs

Cf. A269143.

Formula

Empirical: a(n) = 26*a(n-1) -199*a(n-2) +408*a(n-3) -463*a(n-4) +322*a(n-5) -141*a(n-6) +36*a(n-7) -4*a(n-8) for n>9