A202956 Number of arrays of n+2 integers in -2..2 with sum zero and adjacent elements differing in absolute value.

6, 28, 82, 200, 524, 1724, 5908, 18340, 53680, 162080, 515626, 1651124, 5168256, 15997588, 50018962, 158377344, 502147864, 1584312736, 4991421852, 15779264936, 50053153920, 158866891408, 503893624892, 1598691706648, 5078888702164

Offset

1,1

Comments

Column 2 of A202962.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Example

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

Crossrefs

Cf. A202962.

Sequence in context: A326484 A144945 A308585 * A279915 A300906 A222198

Adjacent sequences: A202953 A202954 A202955 * A202957 A202958 A202959

Keyword

nonn

Author

R. H. Hardin, Dec 26 2011

Status

approved