A201840 Number of zero-sum nX1 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor

0, 1, 1, 3, 1, 9, 7, 25, 25, 83, 85, 277, 327, 965, 1267, 3479, 4933, 12713, 19267, 47079, 75269, 176317, 294185, 665893, 1149735, 2531711, 4492395, 9677791, 17552673, 37160277, 68590367, 143219187, 268096983, 553710855, 1048276003, 2146430287

Offset

1,4

Comments

Column 1 of A201847

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Example

Some solutions for n=9
..0....0...-1....0....0....1....1....0....0....0...-1....0....1....0....1....0
..0....0...-1....0....0....1....1....0....0....0...-1....0....1....0....1....0
..0....0...-1....0...-1...-1....1....0....0....0...-1...-1....0....1....0....0
..1....0....0....1...-1...-1...-1...-1....1...-1....1...-1....0....1....0...-1
..1....0....0....1....0....0...-1...-1....1...-1....1....1....0...-1...-1...-1
..1...-1....0....0....0....0...-1....1...-1...-1....1....1....0...-1...-1....0
.-1...-1....1....0....0....0....0....1...-1....1....0....0....0....0....0....0
.-1....1....1...-1....1....0....0....0....0....1....0....0...-1....0....0....1
.-1....1....1...-1....1....0....0....0....0....1....0....0...-1....0....0....1

Crossrefs

Sequence in context: A210395 A019770 A136320 * A114195 A185948 A016601

Adjacent sequences: A201837 A201838 A201839 * A201841 A201842 A201843

Keyword

nonn

Author

R. H. Hardin Dec 06 2011

Status

approved