A201797 Number of zero-sum nX2 -2..2 arrays with every element unequal to at most two horizontal and vertical neighbors.

5, 85, 455, 3617, 28625, 235827, 1972115, 16703881, 142672901, 1226999941, 10610923603, 92180196507, 803840798219, 7032319990027, 61691173120353, 542479698511869, 4780243712781261, 42200307665852185, 373156481784589911

Offset: 1

Author

R. H. Hardin Dec 05 2011

Keywords

• nonn

Comments

Column 2 of A201803

Examples

			Some solutions for n=5
..2.-1...-2..2...-2..2...-1..2...-2..1....1..2....2..2....0..0....0..0...-1.-2
..2.-1...-2..0....1..1...-1..2....2.-1...-2.-2...-2.-2....2..2....2.-1...-1.-2
..0..0...-2..0....0..0....1.-2....2.-1....2.-2....2..0....0..0....2.-1....2..0
..0..0....2..2...-1.-1....1.-2...-2.-2....2.-2....2..0....0.-1...-1.-1....2..0
..0.-2....1.-1....2.-2....2.-2....1..2....2.-1...-2.-2...-2.-1...-1..1....0..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..126