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 A078552 #10 Aug 01 2019 11:32:30 %S A078552 3,7,73,7,7,43,13,757,7,37,73,157,43,7,151,13,757,7,73,43,37,13,13, %T A078552 829,157,73,73,271,7,19,73,37,13,43,757,43,7,157,13,547,43,139,73,757, %U A078552 13,103,151,1063,829,13,157,919,73,37,43,7,271,163,73,523,19,757,337,157 %N A078552 Largest prime dividing sigma(3,n). %H A078552 Amiram Eldar, <a href="/A078552/b078552.txt">Table of n, a(n) for n = 2..10000</a> %F A078552 a(n) = A006530(A001158(n)). %t A078552 gpf[n_] := FactorInteger[n][[-1, 1]]; a[n_] := gpf[DivisorSigma[3, n]]; Array[a, 65, 2] (* _Amiram Eldar_, Aug 01 2019 *) %Y A078552 Cf. A006530, A001157-A001160, A071190. %K A078552 nonn %O A078552 2,1 %A A078552 _Labos Elemer_, Dec 05 2002