A201957 Number of zero-sum nX4 -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.

231, 17903, 303955, 9654533, 300895245, 10356370455, 360008261031

Offset: 1

Author

R. H. Hardin Dec 06 2011

Keywords

• nonn

Comments

Column 4 of A201958

Examples

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