A199896 Number of -6..6 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative

1, 13, 67, 545, 3573, 27457, 193689, 1462859, 10651367, 80142549, 593254327, 4466635929, 33386730231, 251884546233, 1894568061637, 14327147198653, 108231414777793, 820328179730055, 6216861991058925, 47216885967426099

Offset

1,2

Comments

Column 6 of A199898

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Example

Some solutions for n=6
.-5....3....5...-3...-2....2....2....2...-5....2....0....0...-6....0...-1...-2
..2....0...-4....2....3....0...-5...-3....5...-2....1...-3....5...-2....3....2
.-2....4....2....0....0....2....5....2...-3....3...-5....6....0....3...-6...-3
..6...-4...-5....0...-1...-2...-4...-4....0...-6....5...-2...-2...-1....3....0
..0....0....4....6....1....2....6....4...-1....6...-1....3....0....6...-4....3
.-1...-3...-2...-5...-1...-4...-4...-1....4...-3....0...-4....3...-6....5....0

Crossrefs

Sequence in context: A141956 A290244 A137720 * A213355 A229999 A258618

Adjacent sequences: A199893 A199894 A199895 * A199897 A199898 A199899

Keyword

nonn

Author

R. H. Hardin Nov 11 2011

Status

approved