A302311 Number of 3 X n 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 6, 13, 26, 48, 121, 275, 600, 1296, 2998, 6731, 15022, 33412, 75480, 169232, 379265, 848913, 1907065, 4276079, 9589159, 21494910, 48224727, 108142434, 242526545, 543834226, 1219737296, 2735350513, 6134430103, 13756843652, 30852213480

Offset: 1

Author

R. H. Hardin, Apr 05 2018

Keywords

• nonn

Comments

Row 3 of A302309.

Examples

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

Links

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

Crossrefs

Cf. A302309.

Formula

Empirical: a(n) = a(n-1) +3*a(n-2) -a(n-3) +8*a(n-4) -7*a(n-5) -22*a(n-6) +9*a(n-7) -14*a(n-8) +10*a(n-9) +39*a(n-10) -19*a(n-11) +6*a(n-12) -18*a(n-14) +9*a(n-15) for n>16.