A302618 Number of nX3 0..1 arrays with every element equal to 0, 1, 2 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 17, 25, 71, 191, 498, 1321, 3505, 9240, 24460, 64759, 171268, 453200, 1199361, 3173346, 8396961, 22219739, 58794851, 155576745, 411673594, 1089327367, 2882467725, 7627305260, 20182608868, 53405199549, 141315536296, 373935069260

Offset

1,1

Comments

Column 3 of A302623.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +a(n-2) +4*a(n-3) -4*a(n-4) -4*a(n-5) +a(n-6) -4*a(n-7) -4*a(n-9) for n>11

Example

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

Crossrefs

Cf. A302623.

Sequence in context: A009226 A273022 A273119 * A171227 A061387 A366210

Adjacent sequences: A302615 A302616 A302617 * A302619 A302620 A302621

Keyword

nonn

Author

R. H. Hardin, Apr 10 2018

Status

approved