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Number of n X n binary arrays indicating whether each 2X2 subblock of a larger binary array has lexicographically increasing rows and columns, for some larger (n+1)X(n+1) binary array with rows and columns of the latter in lexicographically nondecreasing order
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%I #5 Dec 18 2015 18:18:36

%S 2,12,99,1339,34862,2016091,272856711,87559140736

%N Number of n X n binary arrays indicating whether each 2X2 subblock of a larger binary array has lexicographically increasing rows and columns, for some larger (n+1)X(n+1) binary array with rows and columns of the latter in lexicographically nondecreasing order

%C Diagonal of A227089

%e Some solutions for n=4

%e ..0..1..1..0....0..1..1..0....0..0..0..0....0..1..0..0....0..0..0..0

%e ..1..1..0..0....1..1..0..1....0..0..0..1....1..1..0..0....0..1..1..0

%e ..1..0..0..0....1..0..0..0....0..0..1..1....0..0..1..1....0..0..0..0

%e ..0..1..0..1....0..0..1..1....0..0..0..0....1..0..1..0....0..0..0..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Jun 30 2013