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A070206 Number of obtuse integer triangles with perimeter n having integral inradius. 3

%I

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

%T 0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,

%U 0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,4,0,0,0,1,0,0

%N Number of obtuse integer triangles with perimeter n having integral inradius.

%C a(n) = A070201(n) - A024155(n) - A070205(n).

%D 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.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Incircle.html">Incircle</a>.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ObtuseTriangle.html">Obtuse Triangle</a>.

%H R. Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a>

%Y Cf. A070141, A070101.

%K nonn

%O 1,84

%A _Reinhard Zumkeller_, May 05 2002

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Last modified May 26 18:08 EDT 2020. Contains 334630 sequences. (Running on oeis4.)