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%I #6 Mar 31 2012 12:36:45
%S 0,1,1,5,1,23,25,97,155,553,893,2945,5721,16499,34509,96903,211929,
%T 571639,1310827,3446631,8106415,21036009,50484447,129556711,315618625,
%U 804915729,1980809241,5032086931,12478845269,31624865741,78861551727
%N Number of zero-sum nX1 -2..2 arrays with every element equal to at least one horizontal or vertical neighbor
%C Column 1 of A201888
%H R. H. Hardin, <a href="/A201884/b201884.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=8
%e ..2...-2....1...-2....0....0....1....1....2....1...-1....0....0...-2...-1....0
%e ..2...-2....1...-2....0....0....1....1....2....1...-1....0....0...-2...-1....0
%e ..0....0....0....2...-2....1....0...-1...-1...-1...-1...-1....0....2...-2....1
%e ..0....0....0....2...-2....1....0...-1...-1...-1...-1...-1....0....2...-2....1
%e .-2....1...-2...-2....1...-2....0...-1....1....2....2...-1....1....0....1....1
%e .-2....1...-2...-2....1...-2....0...-1....1....2....2....1....1....0....1....1
%e ..0....1....1....2....1....1...-1....1...-2...-2....0....1...-1....0....2...-2
%e ..0....1....1....2....1....1...-1....1...-2...-2....0....1...-1....0....2...-2
%K nonn
%O 1,4
%A _R. H. Hardin_ Dec 06 2011
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