A303183 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 25, 31, 72, 170, 382, 873, 2013, 4618, 10598, 24347, 55915, 128406, 294906, 677293, 1555481, 3572366, 8204410, 18842487, 43274223, 99384898, 228250358, 524206673, 1203908917, 2764933650, 6350030286, 14583671731, 33493301843, 76921730606

Offset

1,1

Comments

Row 3 of A303182.

Links

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

Formula

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

Example

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

Crossrefs

Cf. A303182.

Sequence in context: A042889 A042177 A302416 * A175052 A370575 A240164

Adjacent sequences: A303180 A303181 A303182 * A303184 A303185 A303186

Keyword

nonn

Author

R. H. Hardin, Apr 19 2018

Status

approved