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 A156271 #4 Jun 02 2025 01:21:43 %S A156271 2,3,5,7,8,9,11,12,14,15,16,18,20,21,23,24,25,27,29,30,32,34,35,36,38, %T A156271 39,41,43,44,46,48,49,50,52,53,55,57,58,59,61,62,63,65,66,67,69,71,72, %U A156271 74,75,77,79,80,81,83,85,86,88,89,90,92,93,95,96,97,99,100,102,104,105 %N A156271 a(n)=sum(k=1,n,A000002(A078649(k))). %K A156271 nonn %O A156271 1,1 %A A156271 _Benoit Cloitre_, Feb 07 2009