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%I #5 Dec 18 2015 18:18:37
%S 2,8,49,513,10906,498772,48265519,9879827545,4332146485870
%N Number of n X n 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X(n+1) binary array having a sum of three or less, with rows and columns of the latter in lexicographically nondecreasing order
%C Diagonal of A227269
%e Some solutions for n=4
%e ..1..1..1..1....1..1..1..1....1..1..1..1....1..1..1..1....1..1..1..1
%e ..1..0..0..1....1..1..1..1....0..1..1..1....1..1..1..1....1..0..1..1
%e ..1..1..0..1....1..1..1..0....0..1..1..1....0..1..1..1....1..0..1..1
%e ..1..1..1..1....1..0..0..1....0..0..0..0....0..0..0..1....1..0..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Jul 04 2013
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