A303457 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 32, 232, 1690, 12340, 90112, 658204, 4807732, 35118024, 256519346, 1873747524, 13686804048, 99975389852, 730271188300, 5334272943080, 38964248230442, 284614727917460, 2078971032009920, 15185864006789660, 110925290484682724

Offset

1,1

Comments

Row 3 of A303456.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -40*a(n-3) +20*a(n-4) +8*a(n-5) -3*a(n-6) +32*a(n-7) for n>8

Example

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

Crossrefs

Cf. A303456.

Sequence in context: A302736 A033515 A300799 * A303451 A301438 A331334

Adjacent sequences: A303454 A303455 A303456 * A303458 A303459 A303460

Keyword

nonn

Author

R. H. Hardin, Apr 24 2018

Status

approved