A145239 - OEIS

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A145239

1/3 of the number of 3-colorings of an n X n array symmetric under 180 degree rotation.

1, 2, 10, 44, 510, 5224, 141884, 3412572, 218142282, 12364138164, 1864646386404, 249526282773960, 88904892606631308, 28120381445675195736, 23690799052839367018340

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

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

CROSSREFS

Sequence in context: A227852 A347524 A065805 * A068561 A068484 A192704

Adjacent sequences: A145236 A145237 A145238 * A145240 A145241 A145242

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 05 2008

STATUS

approved