A318339 Number of nX4 0..1 arrays with every element unequal to 0, 1, 2 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

8, 20, 36, 67, 148, 343, 817, 1975, 4788, 11644, 28327, 68949, 167840, 408591, 994711, 2421617, 5895464, 14352589, 34941627, 85066013, 207094729, 504175889, 1227425339, 2988189330, 7274801283, 17710636103, 43116865936, 104968794797

Offset: 1

Author

R. H. Hardin, Aug 24 2018

Keywords

• nonn

Comments

Column 4 of A318343.

Examples

			Some solutions for n=5
..0..0..0..0. .0..0..1..1. .0..1..1..0. .0..1..1..1. .0..0..0..0
..0..0..0..0. .0..1..1..1. .1..1..0..0. .1..1..1..1. .0..0..0..0
..0..0..0..0. .1..1..1..1. .1..0..0..0. .1..1..1..1. .0..0..1..0
..0..0..1..0. .1..0..1..1. .0..0..0..0. .0..0..0..0. .0..0..0..0
..0..0..0..1. .1..1..1..1. .0..0..0..1. .0..0..0..1. .0..0..0..1
		

Links

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

Crossrefs

Cf. A318343.

Formula

Empirical: a(n) = a(n-1) +4*a(n-2) +a(n-3) -5*a(n-4) -2*a(n-5) +2*a(n-6) +a(n-7) -a(n-8) for n>9