A070141 - OEIS

%I #6 Mar 30 2012 18:50:21

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

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

%U 0,0,0,3,0,0,0,1,0,1,0,2,0,0,0,4,0,0,0,1,0,2

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

%C a(n) = A051516(n) - A070140(n) - A024155(n).

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HeronianTriangle.html">Heronian Triangle</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. A051516, A070101, A070147.

%K nonn

%O 1,36

%A _Reinhard Zumkeller_, May 05 2002