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A201489 Number of n X n zero-sum -2..2 arrays with rows and columns lexicographically nondecreasing.

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%I A201489 #8 Jul 22 2025 16:16:00
%S A201489 1,29,9331,50432052,4585552158911,7383126698273869479
%N A201489 Number of n X n zero-sum -2..2 arrays with rows and columns lexicographically nondecreasing.
%C A201489 Diagonal of A201496
%e A201489 Some solutions for n=3
%e A201489 .-2..0..1...-2.-2.-1...-1..0..1...-2..0..2...-1.-1..0...-2.-1.-1...-2.-1..2
%e A201489 .-1..0..0...-2..2..2...-1..0..2....0.-2..1...-1..2..1....0.-1..1...-2..2..2
%e A201489 ..1..2.-1....2..2.-1....0.-2..1....0.-1..2....0..0..0....1..1..2...-1..1.-1
%K A201489 nonn
%O A201489 1,2
%A A201489 _R. H. Hardin_ Dec 02 2011

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