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 A073128 #5 Oct 15 2013 22:31:25 %S A073128 0,1,1,5,5,49,118,121,2406,2698,4182,4946,153627,3087192,8203485, %T A073128 38394376,487844934,2822741576,4140154385,4397137572,8583966231 %N A073128 Integer quotients arising in A063986. %F A073128 a(n)=Sum[cototient[j], j=1..A063986(n)]/A063986(n) %e A073128 n=15, A063986(15)=41846733, sum of first 41846733 cototients is s=343289046464505, a(15)=s/41846733. Only in knowledge of either the quotients or of partial sums of cototients is it possible to continue A063986 without recomputing previous terms! %Y A073128 Cf. A051953, A000010, A002088, A048920, A000217, A050226, A063986. %K A073128 more,nonn %O A073128 1,4 %A A073128 _Labos Elemer_, Jul 16 2002 %E A073128 Changed A063896 to A063986 and a(16)-a(21) from _Donovan Johnson_, May 11 2010