A303315 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 4, 12, 17, 24, 67, 158, 298, 595, 1337, 2863, 5840, 12231, 26168, 55140, 115193, 242621, 512713, 1078852, 2267487, 4776110, 10063518, 21181387, 44579665, 93874659, 197672892, 416137435, 876080072, 1844597384, 3883701257, 8176491213

Offset

1,1

Comments

Row 3 of A303314.

Links

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

Formula

Empirical: a(n) = a(n-1) +3*a(n-3) +4*a(n-4) for n>7

Example

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

Crossrefs

Cf. A303314.

Sequence in context: A136485 A157617 A053415 * A331606 A079902 A309128

Adjacent sequences: A303312 A303313 A303314 * A303316 A303317 A303318

Keyword

nonn

Author

R. H. Hardin, Apr 21 2018

Status

approved