A199826 Number of -2..2 arrays x(0..n+1) of n+2 elements with zero sum and no two neighbors summing to zero

10, 40, 114, 426, 1650, 6126, 23206, 88636, 337866, 1295566, 4992364, 19269156, 74529210, 288954786, 1122363984, 4366362420, 17011617426, 66365823648, 259213619826, 1013542247970, 3966939195402, 15540399135516, 60929935280508

Offset

1,1

Comments

Column 2 of A199832

Links

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

Example

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

Crossrefs

Sequence in context: A063490 A251121 A002419 * A227056 A027981 A013977

Adjacent sequences: A199823 A199824 A199825 * A199827 A199828 A199829

Keyword

nonn

Author

R. H. Hardin Nov 11 2011

Status

approved