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 A168128 #13 Feb 22 2020 08:31:04 %S A168128 1,2,23,247,699,55921,70936,152730,478017,4879815,12909834588, %T A168128 223070292558,583407686653,601718433498 %N A168128 Numbers Sum_(j=1..k) sigma(j) / sigma(k) when this expression is an integer. %C A168128 Numbers A024916(k)/A000203(k) when it is an integer. %C A168128 Corresponding values of k, sigma(k) and Sum_(j=1..k) sigma(j) are given in A168127, A168129 and A168130. - _Jaroslav Krizek_, Nov 21 2009 %e A168128 a(3)=23 because A024916(29) / A000203(29) = 690 / 30 = 23 is an integer, where 29 is A168127(3). %o A168128 (PARI) m=0; for(k=1, 11413204, s=sigma(k); m=m+s; if(m%s==0, print1(m/s ", "))) \\ _Donovan Johnson_, Oct 16 2013 %Y A168128 Cf. A000203, A024916, A168127, A168129, A168130. %K A168128 nonn,more %O A168128 1,2 %A A168128 _Jaroslav Krizek_, Nov 18 2009, Dec 04 2009 %E A168128 a(8)-a(10) from _Donovan Johnson_, Oct 16 2013 %E A168128 a(11)-a(14) from _Giovanni Resta_, Jun 06 2016 %E A168128 Name edited by _Michel Marcus_, Feb 22 2020