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 A070208 Number of integer triangles with perimeter n having integral area but not integral inradius. 1

%I

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,

%T 0,2,0,0,0,0,0,0,0,0,0,0,0,2,0,2,0,0,0,3,0,0,0,0,0,0,0,0,0,3,0,0,0,0,

%U 0,0,0,3,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,2

%N Number of integer triangles with perimeter n having integral area but not integral inradius.

%C a(n) = A051516(n) - A070201(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/HeronsFormula.html">Heron's Formula</a>.

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

%K nonn

%O 1,36

%A _Reinhard Zumkeller_, May 05 2002

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Last modified August 13 08:18 EDT 2022. Contains 356079 sequences. (Running on oeis4.)