A089060 - OEIS

%I #3 Oct 01 2013 17:57:46

%S 85,170,184,217,255,340,368,425,434,510,552,564,651,680,736,765,781,

%T 820,850,868,920,935,1020,1085,1104,1105,1128,1261,1264,1275,1302,

%U 1360,1445,1472,1530,1562,1615,1640,1656,1692,1700,1736,1840,1870,1953,1955,2024

%N x = non-multiple of 7 such that xy/(x+y) is an integer and the hypotenuse of the right triangle with legs x and y is an integer.

%e x=85,y=204, 85^2+204^2 = 221^2

%o (PARI) xydivxpynodiv7(n) = { for(x=1,n, for(y=x,n, h=x*y/(x+y); if(h==floor(h), z = sqrt(x^2+y^2); if(z==floor(z) && floor(z)%7, print1(x",") ) ) ) ) }

%K nonn

%O 1,1

%A _Cino Hilliard_, Dec 02 2003