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Number of n X n arrays of squares of integers, symmetric under 90 degree rotation, with all rows summing to 4.
0

%I #4 Dec 18 2015 18:17:16

%S 1,0,0,3,5,12,54,426,2334,23280,152820,1939740,14564760,222925920,

%T 1890254100,33899743010,320743643010,6597891367200,68944295861280,

%U 1600434039456630,18309730315533930,473501454337711800

%N Number of n X n arrays of squares of integers, symmetric under 90 degree rotation, with all rows summing to 4.

%K nonn

%O 1,4

%A _R. H. Hardin_ Feb 09 2009