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Number of isosceles integer triangles with perimeter n having integral area.
5

%I #10 Sep 13 2018 09:30:32

%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 0,2,0,0,0,0,0,0,0,0,0,0,0,1,0,2,0,0,0,1,0,0,0,0,0,0,0,0,0,3,0,0,0,0,

%U 0,0,0,2,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1

%N Number of isosceles integer triangles with perimeter n having integral area.

%C a(n) = A051516(n) - A024153(n).

%H Seiichi Manyama, <a href="/A070139/b070139.txt">Table of n, a(n) for n = 1..1000</a>

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

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

%Y Cf. A051516, A024153, A059169, A070145.

%K nonn

%O 1,36

%A _Reinhard Zumkeller_, May 05 2002