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%I #5 Mar 31 2012 12:36:45
%S 0,1,1,3,1,9,7,25,25,83,85,277,327,965,1267,3479,4933,12713,19267,
%T 47079,75269,176317,294185,665893,1149735,2531711,4492395,9677791,
%U 17552673,37160277,68590367,143219187,268096983,553710855,1048276003,2146430287
%N Number of zero-sum nX1 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor
%C Column 1 of A201847
%H R. H. Hardin, <a href="/A201840/b201840.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=9
%e ..0....0...-1....0....0....1....1....0....0....0...-1....0....1....0....1....0
%e ..0....0...-1....0....0....1....1....0....0....0...-1....0....1....0....1....0
%e ..0....0...-1....0...-1...-1....1....0....0....0...-1...-1....0....1....0....0
%e ..1....0....0....1...-1...-1...-1...-1....1...-1....1...-1....0....1....0...-1
%e ..1....0....0....1....0....0...-1...-1....1...-1....1....1....0...-1...-1...-1
%e ..1...-1....0....0....0....0...-1....1...-1...-1....1....1....0...-1...-1....0
%e .-1...-1....1....0....0....0....0....1...-1....1....0....0....0....0....0....0
%e .-1....1....1...-1....1....0....0....0....0....1....0....0...-1....0....0....1
%e .-1....1....1...-1....1....0....0....0....0....1....0....0...-1....0....0....1
%K nonn
%O 1,4
%A _R. H. Hardin_ Dec 06 2011
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