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 A246456 #11 Sep 08 2022 08:46:09 %S A246456 3,6,8,12,12,39,24,24,36,56,24,90,40,60,56,48,48,80,56,96,54,90,48, %T A246456 224,120,126,68,224,60,216,104,120,121,180,84,128,124,171,120,252,84, %U A246456 288,120,255,168,180,120,308,162,168,168,372,108,360,128,372,138,266 %N A246456 a(n) = sigma(n + sigma(n)). %e A246456 For n = 6; a(n) = sigma(6 + sigma(6)) = sigma(18) = 39. %o A246456 (Magma) [SumOfDivisors(n+SumOfDivisors(n)):n in[1..1000]] %o A246456 (PARI) %o A246456 vector(100,n,sigma(n+sigma(n))) \\ _Derek Orr_, Sep 07 2014 %Y A246456 Cf. A000203, A246909, A246907 (numbers n such that a(n) = 3n), A246915 (numbers n such that a(n) = a(n+1)). %Y A246456 Cf. Sequences of numbers n such that a(n) = k*sigma(n): %Y A246456 A246857 (k=2), A246910 (k=3), A246911 (k=4), A246912 (k=5), A246913 (k=6). %K A246456 nonn %O A246456 1,1 %A A246456 _Jaroslav Krizek_, Sep 07 2014