A145237 1/3 of the number of 3-colorings of an n X n array symmetric about main diagonal.

1, 4, 24, 216, 2952, 61488, 1957392, 95392296, 7125411888, 816458567400, 143601085430064, 38787148664334000, 16094818374887017440, 10263152688155204724288, 10059484565080507620249504

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Crossrefs

Sequence in context: A166881 A334602 A183279 * A034256 A179539 A277612

Adjacent sequences: A145234 A145235 A145236 * A145238 A145239 A145240

Keyword

nonn

Author

R. H. Hardin, Oct 05 2008

Status

approved