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 A387472 #26 Sep 04 2025 14:17:43
%S A387472 1,5,13,87
%N A387472 Numbers k such that the sum of the first k digits of e is divisible by k.
%C A387472 For large n, A046975(n-1)/n is very close to 4.5, so is never an integer. - _Alois P. Heinz_, Sep 02 2025
%F A387472 {k such that k divides A046975(k-1)}. - _Michael S. Branicky_, Aug 30 2025
%e A387472 5 is a term since 2+7+1+8+2 = 20 is divisible by 5.
%t A387472 Module[{nn=20000,ed},ed=RealDigits[E,10,nn][[1]];Select[Range[nn],Mod[Total[Take[ed,#]],#]==0&]]
%Y A387472 Cf. A001113, A046975, A098934.
%K A387472 nonn,base,easy,fini,full,new
%O A387472 1,2
%A A387472 _Harvey P. Dale_, Aug 30 2025