A166200 Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 5

1, 6, 2, 5, 39, 122, 604, 8064, 40848, 495985, 16474555, 153952919, 4118194905, 283350411160, 6779925069586, 398461742491565, 59492448257857640

Offset

0,2

Links

Table of n, a(n) for n=0..16.

Example

Some solutions for n=4
.....1........1........2........0........0........1........0........2...
....1.0......0.1......0.0......1.0......0.0......0.0......0.0......1.0..
...0.1.1....1.1.0....0.0.0....0.0.1....0.3.0....0.1.0....0.0.0....0.1.1.
..1.1.0.1..1.0.1.1..2.0.0.2..0.1.0.0..0.0.0.0..1.0.0.1..0.0.0.0..2.1.0.2
------
.....2........0........3........0........0........2........2........1...
....0.0......0.1......0.0......0.0......0.0......0.1......0.0......1.0..
...0.2.0....1.2.0....0.0.0....0.1.0....0.5.0....1.0.0....0.3.0....0.0.1.
..2.0.0.2..0.0.1.0..3.0.0.3..0.0.0.0..0.0.0.0..2.0.1.2..2.0.0.2..1.1.0.1

Crossrefs

Sequence in context: A193780 A220260 A238901 * A120832 A248271 A021988

Adjacent sequences: A166197 A166198 A166199 * A166201 A166202 A166203

Keyword

nonn

Author

R. H. Hardin Oct 09 2009

Status

approved