A166175 - OEIS

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A166175

Number of nXnXn triangular nonnegative integer arrays with all sums of an element and its neighbors <= 3

1, 4, 20, 90, 1298, 29853, 916190, 57144847, 5975154355, 1004833436277, 297422776532546, 149166709082046028, 125721038997500863278

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..12.

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

Adjacent sequences: A166172 A166173 A166174 * A166176 A166177 A166178

KEYWORD

nonn

AUTHOR

R. H. Hardin Oct 09 2009

STATUS

approved