A070200 Inradii of integer triangles [A070080(n), A070081(n), A070082(n)], rounded values.

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

Offset

1,39

Comments

Triangles [A070080(A070209(n)), A070081(A070209(n)), A070082(A070209(n))] have integer inradii = a(A070209(k))= A070210(k).

Links

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

Eric Weisstein's World of Mathematics, Incircle.

R. Zumkeller, Integer-sided triangles

Formula

a(n) = sqrt((s-u)*(s-v)*(s-w)/s), where u=A070080(n), v=A070081(n), w=A070082(n) and s=A070083(n)/2=(u+v+w)/2.

Example

[A070080(25), A070081(25), A070082(25)] = [3,5,6] and s = A070083(25)/2 = (3+5+6)/2 = 7: a(25) = sqrt((s-3)*(s-5)*(s-6)/7) = sqrt((7-3)*(7-5)*(7-6)/7) = sqrt(4*2*1/7) = sqrt(8/7) = 1.069, rounded = 1.

Crossrefs

Cf. A070086.

Sequence in context: A144474 A298602 A203949 * A359833 A025914 A376631

Adjacent sequences: A070197 A070198 A070199 * A070201 A070202 A070203

Keyword

nonn

Author

Reinhard Zumkeller, May 05 2002

Status

approved