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 A115042 #9 Aug 17 2018 11:44:13 %S A115042 1,2,18,24,35,40,252 %N A115042 Positions of 1's in A094405, "a(n) = sum of all previous terms modulo n, a(1)=1". %C A115042 Positions of 0's: 4, 9, 333. %p A115042 Res:= 1; %p A115042 s:= 1: %p A115042 for n from 2 to 397 do %p A115042 a:= s mod n; %p A115042 s:= s+a; %p A115042 if a = 1 then Res:= Res, n fi; %p A115042 od: %p A115042 Res; # _Robert Israel_, Aug 16 2018 %Y A115042 Cf. A094405. %K A115042 nonn,fini,full %O A115042 1,2 %A A115042 _Zak Seidov_, Feb 27 2006 %E A115042 Keywords fini,full added by _Robert Israel_, Aug 16 2018