A166179 Number of nXnXn triangular nonnegative integer arrays with all sums of an element and its neighbors <= 7

1, 8, 120, 2030, 208269, 53152348, 27693285837, 47961481828069

Offset

0,2

Links

Table of n, a(n) for n=0..7.

Example

Some solutions for n=4
.....3........2........1........4........1........1........0........1...
....1.0......0.0......0.0......2.0......0.0......0.0......2.2......0.4..
...0.2.1....3.0.1....6.0.0....0.0.0....1.3.2....2.0.1....0.0.3....1.0.0.
..1.2.1.0..2.0.1.2..0.0.1.0..2.1.2.2..1.0.1.0..4.0.1.2..2.0.0.0..0.0.1.2
------
.....1........0........5........1........2........0........0........1...
....0.2......0.1......0.1......1.4......1.0......0.0......0.1......1.1..
...1.1.3....0.0.0....1.0.0....1.0.0....0.0.0....0.0.0....0.0.2....1.1.1.
..4.0.0.0..7.0.0.4..0.0.5.0..5.0.1.2..2.0.2.0..3.2.0.2..5.1.0.0..0.0.2.0

Crossrefs

Sequence in context: A045899 A165231 A004381 * A130979 A239226 A133308

Adjacent sequences: A166176 A166177 A166178 * A166180 A166181 A166182

Keyword

nonn

Author

R. H. Hardin Oct 09 2009

Status

approved