A301791 Number of 2Xn 0..1 arrays with every element equal to 0 or 1 horizontally or antidiagonally adjacent elements, with upper left element zero.

2, 5, 6, 9, 14, 22, 35, 56, 90, 145, 234, 378, 611, 988, 1598, 2585, 4182, 6766, 10947, 17712, 28658, 46369, 75026, 121394, 196419, 317812, 514230, 832041, 1346270, 2178310, 3524579, 5702888, 9227466, 14930353, 24157818, 39088170, 63245987

Offset: 1

Author

R. H. Hardin, Mar 26 2018

Keywords

• nonn

Comments

Row 2 of A301790.

Examples

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

Links

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

Crossrefs

Cf. A301790, A020706, A048577.

Formula

Empirical: a(n) = 2*a(n-1) -a(n-3) for n>5.