A201800 - OEIS

%I #8 Oct 03 2025 09:15:50

%S 381,28625,562961,20960485,722587629,27941324053,1077779765471

%N Number of zero-sum nX5 -2..2 arrays with every element unequal to at most two horizontal and vertical neighbors.

%C Column 5 of A201803

%e Some solutions for n=2

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 05 2011