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

1,1

Comments

Column 3 of A201803

Links

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

Example

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

Crossrefs

Sequence in context: A194730 A012506 A285398 * A284197 A081686 A284163

Adjacent sequences: A201795 A201796 A201797 * A201799 A201800 A201801

Keyword

nonn

Author

R. H. Hardin Dec 05 2011

Status

approved