A201799 Number of zero-sum nX4 -2..2 arrays with every element unequal to at most two horizontal and vertical neighbors.

85, 3617, 48335, 988589, 20960485, 472565771, 10857153407, 253641348337, 5979418257253, 142075597768273, 3395164032578079, 81529069984570623, 1965470518289395959

Offset: 1

Author

R. H. Hardin Dec 05 2011

Keywords

• nonn

Comments

Column 4 of A201803

Examples

			Some solutions for n=3
..0.-1..1..0...-2..1..1..0...-2.-2.-1.-1...-1..1.-2..1...-1..2.-2.-2
..0.-1..1..1...-2..1..1..1....2..2..0..0....1..1.-2..1....2..2..0..0
..0.-1..1.-1...-2..1..0..0...-1..2..0..1....0..0.-2..2...-2..0..0..1