A372733 - OEIS

A372733

Number of curved edges among all distinct circles that can be constructed from the 3 vertices and the equally spaced 3*n points placed on the sides of an equilateral triangle when every pair of the 3 + 3*n points are connected by a circle and where the points lie at the ends of the circle's diameter.

12, 138, 738, 2838, 7194, 17904, 33954, 62868, 103866, 167280, 248826, 370458, 511806, 715905, 952608, 1260366

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OFFSET

0,1

COMMENTS

A circle is constructed for every pair of the 3 + 3*n points, the two points lying at the ends of a diameter of the circle.

See A372731 and A372732 for images of the circles.

LINKS

Table of n, a(n) for n=0..15.

FORMULA

a(n) = A372731(n) + A372732(n) - 1 by Euler's formula.

CROSSREFS