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

1,2

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

Links

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

Example

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

Crossrefs

Column 1 is A005191

Sequence in context: A305514 A039914 A274910 * A151789 A339320 A302176

Adjacent sequences: A201800 A201801 A201802 * A201804 A201805 A201806

Keyword

nonn,tabl

Author

R. H. Hardin Dec 05 2011

Status

approved