A145241 - OEIS

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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.

%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