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%I #6 Dec 18 2015 18:17:55
%S 1,15,9880,132636590,26207146328784,75743730886453371522,
%T 3202145671418507455058837791
%N Number of n X n 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors
%C Diagonal of A200801
%e Some solutions for n=3
%e ..0..1..2....0..1..0....0..1..1....0..1..1....0..1..2....0..1..0....0..1..2
%e ..2..0..0....2..2..1....2..1..3....1..1..2....1..1..3....1..1..2....1..1..2
%e ..3..3..1....0..0..3....3..0..2....3..2..2....0..0..3....3..2..0....3..2..2
%K nonn
%O 1,2
%A _R. H. Hardin_ Nov 22 2011
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