A070204 Number of isosceles integer triangles with perimeter n having integral inradius.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset: 1

Author

Reinhard Zumkeller, May 05 2002

Keywords

• nonn

Comments

a(n) = A070201(n) - A070203(n).

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..5000
• Mohammad K. Azarian, Solution to Problem S125: Circumradius and Inradius, Math Horizons, Vol. 16, Issue 2, November 2008, p. 32.
• Eric Weisstein's World of Mathematics, Incircle.
• Eric Weisstein's World of Mathematics, Isosceles Triangle.
• R. Zumkeller, Integer-sided triangles

Crossrefs

Cf. A070139, A059169.