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A145239
1/3 of the number of 3-colorings of an n X n array symmetric under 180 degree rotation.
0
1, 2, 10, 44, 510, 5224, 141884, 3412572, 218142282, 12364138164, 1864646386404, 249526282773960, 88904892606631308, 28120381445675195736, 23690799052839367018340
OFFSET
1,2
CROSSREFS
Sequence in context: A227852 A347524 A065805 * A068561 A068484 A192704
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 05 2008
STATUS
approved