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A209728 1/4 the number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having distinct edge sums.

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%I A209728 #7 Jul 22 2025 21:55:27
%S A209728 22,1096,137888,47572464,45147495264,121396901813560,
%T A209728 914481225452329872,19676655455650623737848
%N A209728 1/4 the number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having distinct edge sums.
%C A209728 Diagonal of A209736
%e A209728 Some solutions for n=4
%e A209728 ..2..3..2..2..3....1..3..2..2..0....3..1..1..1..3....3..3..0..1..0
%e A209728 ..1..1..0..1..1....2..3..0..1..0....2..0..3..2..3....1..2..2..2..0
%e A209728 ..2..3..3..3..0....0..1..0..2..2....1..0..1..0..3....1..3..0..1..0
%e A209728 ..1..1..0..1..1....2..3..3..3..0....1..3..3..0..2....0..2..0..2..0
%e A209728 ..2..3..2..3..0....0..0..2..1..1....0..0..2..0..3....3..2..3..2..3
%K A209728 nonn
%O A209728 1,1
%A A209728 _R. H. Hardin_ Mar 12 2012

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