Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #15 Dec 23 2017 04:16:18
%S 1,2,2,3,2,3,3,2,4,3,4,4,3,2,4,5,3,6,4,6,6,6,4,6,3,4,3,6,4,5,4,3,6,5,
%T 7,8,6,4,6,8,7,8,9,3,9,5,6,9,8,10,6,6,6,9,8,4,8,9,7,10,6,10,12,6,12,
%U 12,5,3,7,8,10,4,9,10,11,6,12,3,6,9,12,12,7,8
%N Inradii of integer triangles [A070080(A070209(n)), A070081(A070209(n)), A070082(A070209(n))].
%C a(n) = A070200(A070209(n)).
%H Mohammad K. Azarian, <a href="http://www.jstor.org/stable/25678790">Solution of problem 125: Circumradius and Inradius</a>, Math Horizons, Vol. 16, No. 2 (Nov. 2008), p. 32.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Incircle.html">Incircle</a>.
%H R. Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a>
%e A070209(3)=212: [A070080(212), A070081(212), A070082(212)] = [5,12,13], let s = A070083(212)/2 = (5+12+13)/2 = 15 then inradius = sqrt((s-5)*(s-5)*(s-6)/s) = sqrt(10*3*2/15) = sqrt(4) = 2; a(3) = A070200(212) = 2.
%Y Cf. A070149, A070201.
%K nonn
%O 1,2
%A _Reinhard Zumkeller_, May 05 2002