A166199 Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 4

1, 5, 2, 4, 25, 64, 249, 2376, 9030, 76249, 1598732, 10091912, 165533393, 6511049130, 90909213960, 2908246084285, 219536965840260, 5801006454694383

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Example

Some solutions for n=4
.....0........1........1........1........1........2........2........3...
....0.0......0.0......0.0......0.1......0.0......1.0......0.0......0.0..
...0.3.0....0.2.0....0.3.0....1.1.0....0.0.0....0.0.1....0.0.0....0.1.0.
..0.0.0.0..1.0.0.1..1.0.0.1..1.0.1.1..1.0.0.1..2.1.0.2..2.0.0.2..3.0.0.3
------
.....1........0........4........1........1........2........2........0...
....1.0......0.0......0.0......1.0......0.1......0.1......0.0......0.1..
...0.1.1....0.1.0....0.0.0....0.0.1....1.0.0....1.0.0....0.1.0....1.0.0.
..1.1.0.1..0.0.0.0..4.0.0.4..1.1.0.1..1.0.1.1..2.0.1.2..2.0.0.2..0.0.1.0

Crossrefs

Sequence in context: A264991 A088507 A050001 * A324860 A373537 A008566

Adjacent sequences: A166196 A166197 A166198 * A166200 A166201 A166202

Keyword

nonn

Author

R. H. Hardin Oct 09 2009

Status

approved