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%I #6 Mar 31 2012 12:36:47
%S 1,3,9,31,107,387,1415,5231,19477,72933,274339,1035807,3923229,
%T 14900005,56721943,216377047,826917803,3165318823,12133973901,
%U 46575395693,178988128029,688588254425,2651686966607,10220607799703,39426825300181
%N Number of zero-sum -2..2 arrays of n elements with adjacent element differences also in -2..2
%C Column 2 of A202252
%H R. H. Hardin, <a href="/A202246/b202246.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=10
%e ..0....2....1...-1...-2....2....0....0...-1....2....1...-1....0....2....1....1
%e ..1....0....0....1....0....0....0...-1....1....2...-1...-1...-1....0...-1....0
%e ..2....0....0...-1...-1...-1....1...-2....1....2....1....1...-1....2...-1...-1
%e ..1...-2...-2....1....0....0...-1....0....0....0....0....1...-1....2....1...-2
%e ..1....0...-2....1....0....2...-2....0...-1...-1...-2....0....1....1...-1....0
%e ..0....0....0...-1....2....0....0....1....0...-2....0...-1...-1...-1....0....0
%e .-1....0....2...-1....1...-2....0....0...-1...-2....2....1....0....0....0....2
%e .-2...-2....1....0....1...-1....0....1....1...-2....0....1....0...-2....0....2
%e .-2....0...-1....1....0....1....0....0....1....0...-1....0....2...-2....0....0
%e ..0....2....1....0...-1...-1....2....1...-1....1....0...-1....1...-2....1...-2
%K nonn
%O 1,2
%A _R. H. Hardin_ Dec 14 2011
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