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

Offset: 0

Author

Scott R. Shannon, May 12 2024

Keywords

• nonn
• more

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.

Crossrefs

Cf. A372731 (vertices), A372732 (regions), A372734 (k-gons), A372735 (number of circles), A372616, A371375, A356358, A360353.

Formula

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