A120569 Number of isosceles triangles with integer sides and inradius n.

0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 3, 0, 0, 2, 1, 0, 1, 0, 2, 2, 0, 0, 5, 0, 0, 1, 1, 0, 3, 0, 1, 1, 0, 1, 4, 0, 0, 1, 3, 0, 3, 0, 1, 2, 0, 0, 5, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 8, 0, 0, 3, 1, 0, 1, 0, 1, 1, 2, 0, 6, 0, 0, 2, 1, 0, 2, 0, 3, 1, 0, 0, 6, 0, 0, 1, 1, 0, 4, 0, 1, 1, 0, 0, 5, 0, 0, 2, 2, 0, 1, 0, 1, 5

Offset

1,12

References

Mohammad K. Azarian, Circumradius and Inradius, Problem S125, Math Horizons, Vol. 15, Issue 4, April 2008, p. 32. Solution published in Vol. 16, Issue 2, November 2008, p. 32.

Links

David W. Wilson, Table of n, a(n) for n = 1..10000

Example

a(24) = 5 because 5 integer-sided isosceles triangles, namely (a,b,c) = (80,80,96), (80,85,85), (90,90,144), (130,130,240), (175,175,336), have inradius 24.

Crossrefs

See A120062 for sequences related to integer-sided triangles with integer inradius n.

Sequence in context: A115979 A067168 A099475 * A128113 A108930 A059682

Adjacent sequences: A120566 A120567 A120568 * A120570 A120571 A120572

Keyword

nonn

Author

David W. Wilson, Jun 17 2006

Status

approved