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A181944 Number of convex quadrilaterals, distinct up to congruence, on an (n X n)-grid (or geoboard). 3
0, 1, 12, 89, 407, 1413 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..6.

Weisstein, Eric W.: MathWorld -- Convex Polygon.

Weisstein, Eric W.: MathWorld -- Quadrilateral.

CROSSREFS

Cf. A189413.

Sequence in context: A009657 A012088 A083825 * A193285 A199558 A034197

Adjacent sequences:  A181941 A181942 A181943 * A181945 A181946 A181947

KEYWORD

nonn

AUTHOR

Martin Renner, Apr 03 2012

STATUS

approved

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Last modified December 15 14:02 EST 2018. Contains 318149 sequences. (Running on oeis4.)