A145238 1/3 of the number of 3-colorings of an n X n array symmetric about both diagonal and antidiagonal.

1, 2, 8, 24, 144, 648, 5904, 40392, 561744, 5871528, 124982208, 2000735640, 65289654720, 1603001126808, 80277953271984, 3025716988718520, 232703590361105952, 13472417658155610888, 1592017750060187494896

Offset

1,2

Links

Table of n, a(n) for n=1..19.

Crossrefs

Sequence in context: A361991 A087982 A176475 * A093458 A242456 A353779

Adjacent sequences: A145235 A145236 A145237 * A145239 A145240 A145241

Keyword

nonn

Author

R. H. Hardin, Oct 05 2008

Status

approved