A302516 Number of 3 X n 0..1 arrays with every element equal to 0, 1, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 4, 11, 15, 21, 52, 118, 220, 408, 852, 1764, 3460, 6796, 13732, 27708, 55140, 109788, 220132, 441244, 881380, 1760796, 3523812, 7051548, 14098660, 28189468, 56387812, 112791324, 225564900, 451098396, 902232292, 1804527388, 3608983780

Offset

1,1

Comments

Row 3 of A302515.

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) +4*a(n-4) for n>7.

Example

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

Crossrefs

Cf. A302515.

Sequence in context: A265206 A327684 A231064 * A254205 A048223 A358825

Adjacent sequences: A302513 A302514 A302515 * A302517 A302518 A302519

Keyword

nonn

Author

R. H. Hardin, Apr 09 2018

Status

approved