A221316 Number of nonnegative integer arrays of length n summing to n without equal adjacent values modulo 3.

1, 2, 6, 8, 19, 44, 84, 212, 474, 1008, 2438, 5436, 12045, 28174, 63292, 142936, 330285, 748286, 1707460, 3930660, 8968641, 20569786, 47335822, 108517496, 249608726, 574843912, 1322068800, 3046723144, 7024972918, 16192943826, 37371650024

Offset

1,2

Comments

Column 3 of A221321.

Links

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

Example

Some solutions for n=6
..0....1....1....4....0....0....2....0....0....1....3....1....0....0....0....1
..1....0....3....0....2....1....1....2....1....0....1....0....1....1....2....0
..2....1....1....1....1....2....0....1....0....2....0....1....3....0....0....1
..0....3....0....0....0....1....2....2....2....0....1....2....1....4....2....0
..1....1....1....1....1....2....1....1....1....1....0....0....0....0....0....1
..2....0....0....0....2....0....0....0....2....2....1....2....1....1....2....3

Crossrefs

Cf. A221321.

Sequence in context: A323859 A365918 A098092 * A106164 A216205 A072230

Adjacent sequences: A221313 A221314 A221315 * A221317 A221318 A221319

Keyword

nonn

Author

R. H. Hardin, Jan 10 2013

Status

approved