A202131 Number of zero-sum nX2 -3..3 arrays with every element equal to at least one horizontal or vertical neighbor

1, 13, 123, 1205, 12287, 135179, 1493247, 16814401, 192346557, 2225951035, 26017190841, 306761764259, 3644115496927, 43571997337907, 523947428428811, 6331638407455241, 76845558853198515, 936178097032511349

Offset

1,2

Comments

Column 2 of A202134

Links

R. H. Hardin, Table of n, a(n) for n = 1..73

Example

Some solutions for n=5
..2..2....2..2...-3.-3....2..1....1..1...-2.-2....1..1....2.-3...-3.-1....1..2
.-1.-1....1.-2....3..3....2..1....3..0....2.-3...-3.-3....2.-3...-3.-1....1..2
..2..2....1.-2....2..2....0..0....3..0....2.-3....1..2...-1.-1....1..2....0..0
..0..0....1.-1...-2..2...-2.-1...-2.-2....1..2....1..2....2..2....1..2....0.-2
.-3.-3...-1.-1...-2.-2...-2.-1...-2.-2....1..2...-1.-1....0..0....1..1...-2.-2

Crossrefs

Sequence in context: A295778 A115204 A016277 * A152583 A304353 A305916

Adjacent sequences: A202128 A202129 A202130 * A202132 A202133 A202134

Keyword

nonn

Author

R. H. Hardin Dec 11 2011

Status

approved