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%I #3 Mar 31 2012 12:35:07
%S 1,3,27,189,3969,64827,3179169,121272795,13891861179,1237840901829,
%T 331231632520635,68946329439933309,43098014529769439457,
%U 20956433266778185286019,30601694853748262964093129
%N 1/4 of the number of 4-colorings of an n X n array symmetric about both diagonal and antidiagonal.
%K nonn
%O 1,2
%A _R. H. Hardin_, Oct 05 2008