A201797 - OEIS

%I #5 Mar 31 2012 12:36:45

%S 5,85,455,3617,28625,235827,1972115,16703881,142672901,1226999941,

%T 10610923603,92180196507,803840798219,7032319990027,61691173120353,

%U 542479698511869,4780243712781261,42200307665852185,373156481784589911

%N Number of zero-sum nX2 -2..2 arrays with every element unequal to at most two horizontal and vertical neighbors

%C Column 2 of A201803

%H R. H. Hardin, <a href="/A201797/b201797.txt">Table of n, a(n) for n = 1..126</a>

%e Some solutions for n=5

%e ..2.-1...-2..2...-2..2...-1..2...-2..1....1..2....2..2....0..0....0..0...-1.-2

%e ..2.-1...-2..0....1..1...-1..2....2.-1...-2.-2...-2.-2....2..2....2.-1...-1.-2

%e ..0..0...-2..0....0..0....1.-2....2.-1....2.-2....2..0....0..0....2.-1....2..0

%e ..0..0....2..2...-1.-1....1.-2...-2.-2....2.-2....2..0....0.-1...-1.-1....2..0

%e ..0.-2....1.-1....2.-2....2.-2....1..2....2.-1...-2.-2...-2.-1...-1..1....0..2

%K nonn

%O 1,1

%A _R. H. Hardin_ Dec 05 2011