A199825 Number of -1..1 arrays x(0..n+1) of n+2 elements with zero sum and no two neighbors summing to zero

2, 4, 4, 10, 22, 34, 66, 138, 250, 472, 944, 1806, 3450, 6772, 13172, 25478, 49794, 97348, 189772, 371246, 727506, 1424586, 2793034, 5483342, 10766950, 21154424, 41599648, 81840866, 161080918, 317230034, 625030514, 1231964394, 2429323642

Offset

1,1

Comments

Column 1 of A199832

Links

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

Example

All solutions for n=3
.-1....0....0....1
.-1....1...-1....1
..0....0....0....0
..1...-1....1...-1
..1....0....0...-1

Crossrefs

Sequence in context: A193852 A327544 A202076 * A121049 A056415 A242993

Adjacent sequences: A199822 A199823 A199824 * A199826 A199827 A199828

Keyword

nonn

Author

R. H. Hardin Nov 11 2011

Status

approved