A201842 Number of zero-sum nX3 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor

1, 25, 125, 2019, 17031, 259811, 2809217, 38543397, 461143387, 6074619247, 75861583015, 986136042011, 12563765990869, 162856252154639, 2096257481229633, 27196201756710491, 352145117477485743

Offset

1,2

Comments

Column 3 of A201847

Links

R. H. Hardin, Table of n, a(n) for n = 1..52

Example

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

Crossrefs

Sequence in context: A074006 A073963 A316277 * A057902 A042216 A042218

Adjacent sequences: A201839 A201840 A201841 * A201843 A201844 A201845

Keyword

nonn

Author

R. H. Hardin Dec 06 2011

Status

approved