A234352 - OEIS

A234352

Number of non-equivalent (mod D_3) ways to arrange 4 indistinguishable points on a triangular grid of side n so that no three points are collinear.

2, 24, 153, 713, 2557, 7661, 20055, 47153, 101821, 205322, 390580, 707708, 1229969, 2060777, 3344487

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OFFSET

3,1

COMMENTS

Column 4 of triangle A234350.

Without the restriction "non-equivalent (mod D_3)" the numbers are given by A194132.

LINKS

EXAMPLE

There are a(3) = 2 non-equivalent ways to arrange 4 indistinguishable points (x) on a triangular grid of side 3:

x .

x x x x

. x . x . x

CROSSREFS

Arranging 3 points: A234351

Arranging 5 points: A234353

Arranging 6 points: A234354

KEYWORD

nonn,more

AUTHOR

EXTENSIONS

a(14)-a(17) from Heinrich Ludwig, Apr 19 2016

STATUS

approved