A201955 Number of zero-sum n X 2 -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.

7, 231, 1587, 17903, 194633, 2232183, 25952953, 305979795, 3640250461, 43624267941, 525774918227, 6366440653727, 77388201173481, 943784967491137, 11542145313593503, 141498452574240619, 1738344524754583621

Offset

1,1

Comments

Column 2 of A201958.

Links

R. H. Hardin, Table of n, a(n) for n = 1..68

Example

Some solutions for n=4
..2..3...-3.-3...-2.-3...-2..3...-2..1....2.-3....2.-3....2..0...-3.-1....1.-2
..0..0....2..2....1..1....0..0...-2..0....1..1....3.-3....0.-1....3..0....0..0
.-2.-2...-1.-1....2..2....1..1....2..0....0..0....3..0....0.-1....3..0....0..0
.-2..1....3..1....0.-1...-1.-2....2.-1...-1..0...-2..0....3.-3...-2..0....3.-2

Crossrefs

Cf. A201958.

Sequence in context: A221495 A343128 A142116 * A081618 A285369 A287042

Adjacent sequences: A201952 A201953 A201954 * A201956 A201957 A201958

Keyword

nonn

Author

R. H. Hardin, Dec 06 2011

Status

approved