A301885 Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

2, 5, 10, 18, 35, 74, 154, 317, 658, 1370, 2851, 5930, 12338, 25677, 53434, 111194, 231395, 481538, 1002090, 2085365, 4339682, 9030962, 18793603, 39109842, 81388322, 169370645, 352463530, 733483298, 1526392675, 3176452154, 6610257274

Offset

1,1

Comments

Row 2 of A301884.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +a(n-3) -a(n-4) -2*a(n-6) +a(n-7)

Example

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

Crossrefs

Cf. A301884.

Sequence in context: A224364 A327064 A246840 * A360811 A127297 A018739

Adjacent sequences: A301882 A301883 A301884 * A301886 A301887 A301888

Keyword

nonn

Author

R. H. Hardin, Mar 28 2018

Status

approved