A145242 1/4 of the number of 4-colorings of an n X n array symmetric under 180 degree rotation.

1, 3, 51, 813, 75351, 6514173, 3287790591, 1547899100553, 4259466117807411, 10935733441872804453, 164161963716080866194651

Offset

1,2

Links

Table of n, a(n) for n=1..11.

Crossrefs

Sequence in context: A045489 A232453 A248341 * A182512 A378552 A075869

Adjacent sequences: A145239 A145240 A145241 * A145243 A145244 A145245

Keyword

nonn

Author

R. H. Hardin, Oct 05 2008

Status

approved