Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the 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