A199907 Number of -6..6 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2)

1, 8, 84, 448, 3196, 29864, 216530, 1699268, 14546928, 116482068, 950119628, 7969545520, 65812921362, 546169532636, 4575686136942, 38231452993064, 320077674218718, 2689588505089064, 22606933344228744, 190257872374203952

Offset

1,2

Comments

Column 6 of A199909

Links

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

Example

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

Crossrefs

Sequence in context: A238811 A307829 A039939 * A264710 A143868 A130591

Adjacent sequences: A199904 A199905 A199906 * A199908 A199909 A199910

Keyword

nonn

Author

R. H. Hardin Nov 11 2011

Status

approved