A320397 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

4, 28, 142, 732, 3694, 18754, 94842, 480321, 2431390, 12309913, 62320210, 315508545, 1597316261, 8086701105, 40940363689, 207267894413, 1049330682760, 5312423710470, 26895092511498, 136161202337290, 689340370573277

Offset

1,1

Comments

Column 3 of A320402.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +11*a(n-2) -a(n-3) -8*a(n-4) -a(n-5) -26*a(n-6) -5*a(n-7) +18*a(n-8) +5*a(n-9) -5*a(n-10) -4*a(n-11) -a(n-12) for n>14

Example

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

Crossrefs

Cf. A320402.

Sequence in context: A051536 A273565 A273558 * A273611 A043013 A145544

Adjacent sequences: A320394 A320395 A320396 * A320398 A320399 A320400

Keyword

nonn

Author

R. H. Hardin, Oct 12 2018

Status

approved