A304216 Number of n X 3 0..1 arrays with every element unequal to 0, 1, 3 or 8 king-move adjacent elements, with upper left element zero.

3, 7, 10, 17, 32, 56, 93, 159, 279, 484, 829, 1426, 2468, 4265, 7349, 12669, 21870, 37749, 65116, 112324, 193813, 334427, 576983, 995444, 1717497, 2963334, 5112744, 8821129, 15219457, 26258869, 45305486, 78167201, 134864984, 232688208

Offset

1,1

Comments

Column 3 of A304221.

Links

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

Formula

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

Example

Some solutions for n=7:
..0..0..0. .0..0..0. .0..0..0. .0..0..1. .0..0..0. .0..0..1. .0..1..1
..0..0..0. .0..1..0. .0..1..0. .0..1..1. .0..0..0. .0..1..1. .0..0..1
..0..0..0. .0..0..0. .0..0..0. .1..1..1. .0..0..0. .1..1..1. .0..0..0
..0..0..0. .0..0..0. .0..0..0. .1..1..1. .0..1..0. .1..1..1. .0..0..0
..0..0..1. .0..0..0. .0..0..0. .1..0..1. .0..0..0. .1..1..1. .0..0..1
..0..1..1. .0..0..0. .0..0..1. .1..1..1. .0..0..0. .0..1..1. .0..1..1
..1..1..1. .0..0..0. .0..1..1. .1..1..1. .1..0..0. .0..0..1. .1..1..1

Crossrefs

Cf. A304221.

Sequence in context: A111244 A022120 A041191 * A305247 A316547 A041251

Adjacent sequences: A304213 A304214 A304215 * A304217 A304218 A304219

Keyword

nonn

Author

R. H. Hardin, May 08 2018

Status

approved