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%I #6 Mar 09 2015 00:18:00
%S 1,2,1,15,8,417,135,42176,10425,15701273,2699264,21418970801,
%T 2653515137,107224417436160,9445766123241,1968910887183791359,
%U 123951426556200960,132633131268024896655873,5955955433730968860975
%N Number of n X n binary matrices, symmetric under horizontal and vertical reflection, with no more than 3 ones in any 2 X 2 subblock.
%H R. H. Hardin, <a href="/A141510/b141510.txt">Table of n, a(n) for n = 0..30</a>
%K nonn
%O 0,2
%A _R. H. Hardin_, Aug 10 2008