A166198 Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 3.

1, 4, 2, 3, 14, 30, 89, 553, 1588, 8865, 104510, 444424, 4173156, 81325310, 652489468, 10459516337, 342881668736, 4580518588744, 125220290825340, 7022575980797573, 156952369257684587

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Example

All solutions for n=4
.....1........0........0........2........1........1........0........0...
....0.1......0.1......0.0......0.0......0.0......0.0......0.0......1.0..
...1.0.0....1.0.0....0.2.0....0.1.0....0.1.0....0.2.0....0.3.0....0.0.1.
..1.0.1.1..0.0.1.0..0.0.0.0..2.0.0.2..1.0.0.1..1.0.0.1..0.0.0.0..0.1.0.0
------
.....0........1........1........0........2........3...
....0.0......1.0......0.0......0.0......0.0......0.0..
...0.0.0....0.0.1....0.0.0....0.1.0....0.0.0....0.0.0.
..0.0.0.0..1.1.0.1..1.0.0.1..0.0.0.0..2.0.0.2..3.0.0.3

Crossrefs

Sequence in context: A341055 A098046 A338247 * A248252 A117238 A197291

Adjacent sequences: A166195 A166196 A166197 * A166199 A166200 A166201

Keyword

nonn

Author

R. H. Hardin, Oct 09 2009

Status

approved