A201839 Number of zero-sum n X n -1..1 arrays with every element equal to at least one horizontal or vertical neighbor

0, 5, 125, 54773, 109797321, 1759241274383

Offset

1,2

Comments

Diagonal of A201847

Links

Table of n, a(n) for n=1..6.

Example

Some solutions for n=4
.-1..1..1..1...-1.-1..1..0...-1.-1..1..1...-1.-1.-1.-1...-1..1.-1.-1
.-1.-1.-1..1...-1..1..1..0....0.-1..0..0....0..1..0..0...-1..1..1.-1
..1.-1..1.-1....0..0.-1.-1....0..1..1..0....0..1.-1.-1....0..0..0..0
..1.-1..1.-1....1..1..0..0....0..1.-1.-1....1..1..1..1....0..1..1..0

Crossrefs

Sequence in context: A109345 A194502 A229868 * A234609 A278080 A156956

Adjacent sequences: A201836 A201837 A201838 * A201840 A201841 A201842

Keyword

nonn

Author

R. H. Hardin Dec 06 2011

Status

approved