A201956 Number of zero-sum nX3 -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.

37, 1587, 17091, 303955, 4735345, 85454789, 1489376611, 27222524599, 493561989579, 9124430335331, 168519041238653, 3142665027511853, 58661584782394781, 1101133968614654601, 20697996312691430763

Offset: 1

Author

R. H. Hardin Dec 06 2011

Keywords

• nonn

Comments

Column 3 of A201958

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..20