This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A120831 #4 Mar 30 2012 18:50:54 %S A120831 1,11,5,16,269,919,1019,6287,6749,192799,68513,629908,131816,5366365, %T A120831 16894967,206416733,212790815,221539555,1140147647,394400219, %U A120831 24027859197,390223473936,399480111942,1236227094836,95391734575399 %N A120831 Numerators of partial sums of (p+q)/p*q, where p and q are primes. %C A120831 Denominators: A120832(n); %C A120831 a(n)/A120832(n) = Sum(A068318(n)/A001358(n):1<=k<=n). %e A120831 n=5: (2+2)/2*2+(2+3)/2*3+(3+3)/3*3+(2+5)/2*5+(2+7)/2*7 = %e A120831 4/4 + 5/6 + 6/9 + 7/10 + 9/14 = 269/70 = a(5)/A120832(5). %Y A120831 Cf. A120835, A120833. %K A120831 nonn,frac %O A120831 1,2 %A A120831 _Reinhard Zumkeller_, Jul 24 2006