A199698 Number of -2..2 arrays x(0..n-1) of n elements with zero sum and no two neighbors equal

1, 4, 14, 52, 200, 708, 2642, 10000, 37984, 144876, 554120, 2128672, 8204180, 31697564, 122734614, 476170124, 1850664202, 7204005752, 28081918548, 109604285492, 428278469018, 1675246478864, 6559126501510, 25703606447364

Offset

1,2

Comments

Column 2 of A199704

Links

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

Example

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

Crossrefs

Sequence in context: A017947 A244898 A244935 * A052710 A364410 A262594

Adjacent sequences: A199695 A199696 A199697 * A199699 A199700 A199701

Keyword

nonn

Author

R. H. Hardin Nov 09 2011

Status

approved