A201803 T(n,k)=Number of zero-sum nXk -2..2 arrays with every element unequal to at most two horizontal and vertical neighbors.

1, 5, 5, 19, 85, 19, 85, 455, 455, 85, 381, 3617, 4057, 3617, 381, 1751, 28625, 48335, 48335, 28625, 1751, 8135, 235827, 562961, 988589, 562961, 235827, 8135, 38165, 1972115, 7099021, 20960485, 20960485, 7099021, 1972115, 38165, 180325, 16703881

Offset: 1

Author

R. H. Hardin Dec 05 2011

Keywords

• nonn
• tabl

Comments

Table starts

......1.........5.........19..........85.........381........1751..........8135

......5........85........455........3617.......28625......235827.......1972115

.....19.......455.......4057.......48335......562961.....7099021......90062519

.....85......3617......48335......988589....20960485...472565771...10857153407

....381.....28625.....562961....20960485...722587629.27941324053.1077779765471

...1751....235827....7099021...472565771.27941324053

...8135...1972115...90062519.10857153407

..38165..16703881.1168520339

.180325.142672901

.856945

Examples

			Some solutions for n=4 k=3
.-1..1.-2....2..2.-2...-2..2..2....0..1..2....0..1..1....2..0..0....0.-1..2
.-1..1..1...-2..2.-2....2..2..2...-2..1..1...-1.-1..1....1..0..0....1.-1.-1
..0..1..1...-2..2.-2...-2.-2.-2...-2..1..1...-1.-1.-1....1.-1.-1....1..1..1
..0..0.-1...-1..2..1....1.-2.-1...-1.-1.-1....2..2.-2...-2.-1..1...-1.-1.-1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..60

Crossrefs

Column 1 is A005191