login
A166201
Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 6
1
1, 7, 3, 7, 66, 218, 1340, 25771, 157803, 2661967, 140020892, 1770255356, 73044448611, 8966527587527, 317675182498031
OFFSET
0,2
EXAMPLE
Some solutions for n=4
.....1........2........0........1........0........4........3........1...
....0.0......0.0......1.0......0.1......1.1......0.0......1.0......1.0..
...0.5.0....0.1.0....0.1.1....1.1.0....1.0.1....0.0.0....0.1.1....0.3.1.
..1.0.0.1..2.0.0.2..0.1.0.0..1.0.1.1..0.1.1.0..4.0.0.4..3.1.0.3..1.1.0.1
------
.....0........0........4........3........1........3........0........3...
....0.0......0.0......0.0......0.1......1.0......1.0......0.0......1.1..
...0.4.0....0.3.0....0.1.0....1.1.0....0.1.1....0.0.1....0.6.0....1.0.1.
..0.0.0.0..0.0.0.0..4.0.0.4..3.0.1.3..1.1.0.1..3.1.0.3..0.0.0.0..3.1.1.3
CROSSREFS
Sequence in context: A247950 A256844 A346538 * A248281 A111197 A372778
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 09 2009
STATUS
approved