A070147 Numbers k such that [A070080(k), A070081(k), A070082(k)] is an obtuse integer triangle with integer area.

52, 252, 368, 372, 561, 659, 839, 957, 1156, 1186, 1204, 1582, 1912, 1920, 1971, 2115, 2713, 2774, 2790, 3251, 3473, 3728, 3746, 4286, 4307, 4313, 4330, 5008, 5272, 5374, 6369, 6389, 6432, 6776, 6881, 7223, 7310, 7341

Offset: 1

Author

Reinhard Zumkeller, May 05 2002

Keywords

• nonn

Examples

			a(1)=52: [A070080(52), A070081(52), A070082(52)] = [5,5,8]: A070085(52)=5^2+5^2-8^2=-14<0 and area^2 = s*(s-5)*(s-5)*(s-6) with s=A070083(52)/2=(5+5+8)/2=9, area^2=9*4*4*1=16*9 is an integer square, therefore A070086(52)=area=4*3=12.
		

Links

• Eric Weisstein's World of Mathematics, Heronian Triangle.
• Eric Weisstein's World of Mathematics, Obtuse Triangle.
• Reinhard Zumkeller, Integer-sided triangles

Crossrefs

Cf. A070142, A070136, A070146, A070141.