A304770 Number of n X 3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 7 king-move adjacent elements, with upper left element zero.

4, 21, 27, 67, 139, 303, 685, 1511, 3316, 7349, 16265, 35899, 79332, 175408, 387618, 856555, 1893162, 4184055, 9246710, 20435743, 45164387, 99815208, 220596189, 487529334, 1077464178, 2381248108, 5262677458, 11630780579, 25704601383

Offset

1,1

Comments

Column 3 of A304775.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-2) +3*a(n-3) +2*a(n-4) -a(n-5) for n>8.

Example

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

Crossrefs

Cf. A304775.

Sequence in context: A356357 A276400 A376222 * A316513 A273208 A273270

Adjacent sequences: A304767 A304768 A304769 * A304771 A304772 A304773

Keyword

nonn

Author

R. H. Hardin, May 18 2018

Status

approved