A166202 Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 7

1, 8, 3, 8, 99, 364, 2718, 70603, 526484, 11908924, 931368996, 15702838676, 958018305487, 191827791698093

Offset

0,2

Links

Table of n, a(n) for n=0..13.

Example

Some solutions for n=4
.....2........0........3........4........0........2........3........0...
....0.2......1.0......0.0......1.0......1.1......1.1......0.1......0.1..
...2.1.0....0.1.1....0.1.0....0.0.1....1.0.1....1.0.1....1.1.0....1.4.0.
..2.0.2.2..0.1.0.0..3.0.0.3..4.1.0.4..0.1.1.0..2.1.1.2..3.0.1.3..0.0.1.0
------
.....0........1........2........1........2........4........7........0...
....1.0......1.0......0.1......0.0......1.0......1.0......0.0......1.1..
...0.3.1....0.2.1....1.1.0....0.5.0....0.1.1....0.1.1....0.0.0....1.1.1.
..0.1.0.0..1.1.0.1..2.0.1.2..1.0.0.1..2.1.0.2..4.1.0.4..7.0.0.7..0.1.1.0

Crossrefs

Sequence in context: A250129 A099724 A024568 * A146482 A019938 A170937

Adjacent sequences: A166199 A166200 A166201 * A166203 A166204 A166205

Keyword

nonn

Author

R. H. Hardin Oct 09 2009

Status

approved