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 A168130 #18 Feb 22 2020 08:31:16 %S A168130 1,8,690,109668,1235133,5475784320,6118230000,28361961000, %T A168130 279467858880,107135567314230,227917248343616414016, %U A168130 79758963630439261338240,413838290195487519174516,638755027963568013738240 %N A168130 Numbers Sum_(j=1..k) sigma(j) when Sum_(j=1..k) sigma(j) / sigma(k) is an integer. %C A168130 Numbers A024916(k) when A024916(k) / A000203(k) is an integer. %C A168130 Corresponding values of k, sigma(k), and Sum_(j=1..k) sigma(j)/sigma(k) are given in A168127, A168129, and A168128. - _Jaroslav Krizek_, Nov 21 2009 %F A168130 a(n) = A024916(A168127(n)). - _Michel Marcus_, Feb 22 2020 %e A168130 a(3)= 690 = A024916(29) because A024916(29) / A000203(29) = 690 / 30 = 23 is an integer, where 29 is A168127(3). %o A168130 (PARI) m=0; for(k=1, 11413204, s=sigma(k); m=m+s; if(m%s==0, print1(m ", "))) \\ _Donovan Johnson_, Oct 16 2013 %Y A168130 Cf. A000203, A024916, A168127, A168128, A168129. %K A168130 nonn,more %O A168130 1,2 %A A168130 _Jaroslav Krizek_, Nov 18 2009, Dec 04 2009 %E A168130 a(8)-a(10) from _Donovan Johnson_, Oct 16 2013 %E A168130 a(11)-a(14) from _Giovanni Resta_, Jun 06 2016 %E A168130 Name edited by _Michel Marcus_, Feb 22 2020