A199700 Number of -4..4 arrays x(0..n-1) of n elements with zero sum and no two neighbors equal

1, 8, 52, 380, 2734, 20116, 149942, 1128388, 8545180, 65055556, 497505902, 3818857188, 29405977172, 227044808964, 1757143904470, 13626887453432, 105870556547144, 823864569255344, 6420445347122416, 50100342760566184

Offset

1,2

Comments

Column 4 of A199704

Links

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

Example

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

Crossrefs

Sequence in context: A155590 A130153 A359126 * A302865 A116171 A303966

Adjacent sequences: A199697 A199698 A199699 * A199701 A199702 A199703

Keyword

nonn

Author

R. H. Hardin Nov 09 2011

Status

approved