A302266 Number of 2Xn 0..1 arrays with every element equal to 0, 1, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

2, 8, 29, 105, 384, 1405, 5135, 18766, 68589, 250693, 916272, 3348929, 12240187, 44737350, 163513041, 597632937, 2184322000, 7983600501, 29179707415, 106650542494, 389803024901, 1424712848861, 5207262571120, 19032314831801

Offset: 1

Author

R. H. Hardin, Apr 04 2018

Keywords

• nonn

Comments

Row 2 of A302265.

Examples

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

Links

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

Crossrefs

Cf. A302265.

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) +4*a(n-3) +4*a(n-4)