A302368 Number of 2Xn 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

2, 2, 12, 20, 72, 168, 496, 1296, 3616, 9760, 26816, 73024, 199808, 545408, 1490688, 4071680, 11125248, 30392832, 83037184, 226857984, 619792384, 1693296640, 4626182144, 12638949376, 34530271232, 94338424832, 257737408512

Offset

1,1

Comments

Row 2 of A302367.

Links

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

Formula

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

Example

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

Crossrefs

Cf. A302367.

Sequence in context: A265458 A054916 A194767 * A346757 A202669 A178845

Adjacent sequences: A302365 A302366 A302367 * A302369 A302370 A302371

Keyword

nonn

Author

R. H. Hardin, Apr 06 2018

Status

approved