A303508 Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 20, 78, 420, 2088, 9916, 49740, 245904, 1204720, 5966528, 29461128, 145208512, 717277504, 3540859200, 17473224048, 86264173904, 425824598480, 2101839903376, 10375467545712, 51215782794640, 252809675084016, 1247933698121232

Offset

1,1

Comments

Column 3 of A303513.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +6*a(n-2) +36*a(n-3) -58*a(n-4) -116*a(n-5) -196*a(n-6) -160*a(n-7) -36*a(n-8) -240*a(n-9) -64*a(n-10) +232*a(n-11) +184*a(n-12) -64*a(n-14)

Example

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

Crossrefs

Cf. A303513.

Sequence in context: A145563 A125669 A295116 * A258627 A082138 A074358

Adjacent sequences: A303505 A303506 A303507 * A303509 A303510 A303511

Keyword

nonn

Author

R. H. Hardin, Apr 25 2018

Status

approved