A221315 Number of nonnegative integer arrays of length n summing to n without equal adjacent values modulo 2

1, 0, 3, 8, 5, 0, 28, 72, 45, 0, 286, 728, 455, 0, 3060, 7752, 4845, 0, 33649, 85008, 53130, 0, 376740, 950040, 593775, 0, 4272048, 10759232, 6724520, 0, 48903492, 123047496, 76904685, 0, 563921995, 1417861016, 886163135, 0, 6540715896, 16435645072

Offset

1,3

Comments

Column 2 of A221321

Solutions must alternate even-odd, and cannot have an odd number of those pairs for even n, so a(n)=0 for n modulo 4 = 2

Links

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

Example

All solutions for n=5
..1....1....1....1....3
..0....0....0....2....0
..3....1....1....1....1
..0....0....2....0....0
..1....3....1....1....1

Crossrefs

Sequence in context: A322470 A016670 A021726 * A131653 A011239 A261644

Adjacent sequences: A221312 A221313 A221314 * A221316 A221317 A221318

Keyword

nonn

Author

R. H. Hardin Jan 10 2013

Status

approved