A301952 Number of 3Xn 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

0, 5, 20, 123, 680, 4070, 23565, 138014, 805249, 4704141, 27469522, 160428571, 936897912, 5471539885, 31953953498, 186612354231, 1089822896327, 6364606387628, 37169536347339, 217071469820879, 1267705419106309

Offset

1,2

Comments

Row 3 of A301951.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +12*a(n-2) -5*a(n-3) -14*a(n-4) +14*a(n-6) +4*a(n-7) -3*a(n-8) -5*a(n-9) +a(n-10) for n>12

Example

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

Crossrefs

Cf. A301951.

Sequence in context: A054720 A208941 A209069 * A110373 A081067 A318250

Adjacent sequences: A301949 A301950 A301951 * A301953 A301954 A301955

Keyword

nonn

Author

R. H. Hardin, Mar 29 2018

Status

approved