A201798 Number of zero-sum nX3 -2..2 arrays with every element unequal to at most two horizontal and vertical neighbors.

19, 455, 4057, 48335, 562961, 7099021, 90062519, 1168520339, 15269686011, 201396758073, 2670595602167, 35597100656221, 476317522683397, 6395415423401799, 86112911010980123, 1162374111689802707

Offset: 1

Author

R. H. Hardin Dec 05 2011

Keywords

• nonn

Comments

Column 3 of A201803

Examples

			Some solutions for n=4
.-2.-2.-2....1.-1..1....1..1.-2....0..1..1...-1..0..0....1..1.-2....1.-2..2
..2..2..2....0.-1..2...-2.-2..2....2..2..2....1..1..1....1..1.-2...-2.-2..2
.-1.-1.-1....0.-1..2....2.-2..2...-2.-2.-2....0..1..1...-1..1..1....2..2..2
..2.-1..2...-2.-1..0....2.-2..0...-1.-1..0....0.-2.-2...-1.-1..1...-2.-2.-1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..40