A199703 Number of -7..7 arrays x(0..n-1) of n elements with zero sum and no two neighbors equal

1, 14, 156, 1940, 24394, 314532, 4099204, 53901956, 713719390, 9503449352, 127119684220, 1706849222504, 22991898594206, 310564824249656, 4205016717658718, 57054704774633892, 775562100878527252

Offset

1,2

Comments

Column 7 of A199704

Links

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

Example

Some solutions for n=5
.-4....2....0....6....3....2...-1...-1....2....2...-4...-1....3....4....2...-4
..1...-7...-1...-4....2...-5....3...-6....0....3...-1....6...-4...-3....0....7
..4....2....6...-5...-2...-6...-5....4...-1...-5....6...-2...-6...-5...-3...-2
.-1...-1...-1...-1...-3....3....6....1....0....6...-7...-4....1...-1....4....6
..0....4...-4....4....0....6...-3....2...-1...-6....6....1....6....5...-3...-7

Crossrefs

Sequence in context: A078999 A016157 A238770 * A144166 A122187 A268946

Adjacent sequences: A199700 A199701 A199702 * A199704 A199705 A199706

Keyword

nonn

Author

R. H. Hardin Nov 09 2011

Status

approved