A070202 Number of integer triangles with perimeter n, integer inradius and side lengths that are not relatively prime.

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, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 3, 0, 0, 0, 1, 0, 1

Offset

1,60

Links

Table of n, a(n) for n=1..90.

Eric Weisstein's World of Mathematics, Incircle.

Reinhard Zumkeller, Integer-sided triangles

Example

For perimeter 24, only the triangle with a=6, b=8, c=10 has an integer inradius (2), therefore a(24)=1. The next examples are a(32)=1 with a=10, b=10, c=12 and a(36)=1 with a=9, b=12, c=15.

Crossrefs

Cf. A070138, A051493, A070109, A070209.

Sequence in context: A320751 A263764 A325668 * A280129 A227344 A130207

Adjacent sequences: A070199 A070200 A070201 * A070203 A070204 A070205

Keyword

nonn,changed

Author

Reinhard Zumkeller, May 05 2002

Extensions

Definition corrected by Georg Fischer, Apr 04 2024

Status

approved