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%I #5 Mar 31 2012 12:37:01
%S 256,51680,47834122,59151473070,211637634795580
%N Number of (n+1)X(n+1) 0..3 arrays with the sums of 2X2 subblocks nondecreasing rightwards and downwards
%C Diagonal of A204309
%e Some solutions for n=4
%e ..0..2..3..0..1....3..1..1..2..0....2..2..2..2..3....1..0..1..2..1
%e ..1..1..1..3..3....0..3..2..2..3....2..2..3..2..2....1..0..1..1..1
%e ..1..2..3..3..2....3..1..1..3..2....2..2..2..2..3....3..2..3..1..3
%e ..1..1..2..3..3....1..2..3..2..3....3..2..3..2..2....0..1..1..3..2
%e ..3..2..3..3..2....2..2..3..2..3....1..3..1..3..2....3..2..3..2..2
%K nonn
%O 1,1
%A _R. H. Hardin_ Jan 14 2012