A226865 - OEIS

%I #5 Dec 18 2015 18:18:36

%S 2,13,187,6195,523701,119835087,77611438870

%N Number of n X n (-1,0,1) arrays of determinants of 2X2 subblocks of some (n+1)X(n+1) binary array with rows and columns of the latter in lexicographically nondecreasing order

%C Diagonal of A226870

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jun 20 2013