A304225 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 7 king-move adjacent elements, with upper left element zero.

4, 3, 5, 6, 11, 16, 22, 33, 49, 71, 104, 153, 224, 328, 481, 705, 1033, 1514, 2219, 3252, 4766, 6985, 10237, 15003, 21988, 32225, 47228, 69216, 101441, 148669, 217885, 319326, 467995, 685880, 1005206, 1473201, 2159081, 3164287, 4637488, 6796569

Offset

1,1

Comments

Column 3 of A304230.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-3) for n>5

Example

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

Crossrefs

Cf. A304230.

Sequence in context: A328109 A000211 A059902 * A068982 A317530 A171021

Adjacent sequences: A304222 A304223 A304224 * A304226 A304227 A304228

Keyword

nonn

Author

R. H. Hardin, May 08 2018

Status

approved