A299589 Number of n X n 0..1 arrays with every element unequal to 0, 1 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 1, 5, 23, 113, 576, 2583, 11656, 54738, 252959, 1159927, 5359097, 24760544, 114126327, 526426848, 2429504050, 11207820807, 51702119063, 238537489057, 1100501704736, 5077031912807, 23422773519432, 108060889914594

Offset: 1

Author

R. H. Hardin, Feb 13 2018

Keywords

• nonn

Comments

Diagonal of A299595.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..70

Crossrefs

Cf. A299595.

Formula

Empirical: a(n) = 3*a(n-1) +2*a(n-2) +28*a(n-3) -2*a(n-4) -42*a(n-5) -56*a(n-6) +50*a(n-7) -44*a(n-8) +30*a(n-9) -44*a(n-10) +2*a(n-11) +2*a(n-12) -a(n-14) +a(n-15) for n>18.