%I #4 Dec 18 2015 18:17:18
%S 7,20,45,95,193,389,777,1553,3097,6185,12345,24665,49273,98489,196857,
%T 393593,786937,1573625,3146745,6292985,12584953,25168889,50335737,
%U 100669433,201334777,402665465
%N 1/4 the number of n X n arrays of squares of integers with every 2X2 subblock summing to 21
%K nonn
%O 2,1
%A _R. H. Hardin_ Apr 06 2009