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A145241 1/4 of the number of 4-colorings of an n X n array symmetric about both diagonal and antidiagonal. 0
1, 3, 27, 189, 3969, 64827, 3179169, 121272795, 13891861179, 1237840901829, 331231632520635, 68946329439933309, 43098014529769439457, 20956433266778185286019, 30601694853748262964093129 (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: A127222 A248225 A251732 * A118996 A267947 A230170
Adjacent sequences: A145238 A145239 A145240 * A145242 A145243 A145244
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 05 2008
STATUS
approved

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Last modified May 29 05:33 EDT 2024. Contains 372921 sequences. (Running on oeis4.)