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A166175
Number of nXnXn triangular nonnegative integer arrays with all sums of an element and its neighbors <= 3
0
1, 4, 20, 90, 1298, 29853, 916190, 57144847, 5975154355, 1004833436277, 297422776532546, 149166709082046028, 125721038997500863278
OFFSET
0,2
EXAMPLE
Some solutions for n=4
.....0........0........0........0........1........1........1........1...
....1.0......0.0......1.0......1.0......1.0......0.0......0.0......0.0..
...0.0.1....0.1.1....0.0.1....0.0.0....1.0.0....0.1.0....0.0.2....2.0.1.
..2.0.0.0..1.0.0.1..0.1.0.1..0.0.1.0..0.0.1.2..0.1.1.0..2.0.0.0..0.0.0.1
------
.....0........1........1........3........0........0........0........0...
....1.1......0.0......0.1......0.0......0.0......1.1......0.0......0.0..
...1.0.0....0.0.0....0.0.0....0.0.0....1.1.0....0.1.0....1.0.0....0.0.1.
..1.0.0.0..0.1.1.1..0.0.0.1..1.0.2.0..0.1.0.0..0.0.0.1..1.0.1.2..0.2.0.0
CROSSREFS
Sequence in context: A229245 A328153 A070733 * A094971 A239650 A218837
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 09 2009
STATUS
approved