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 A031236 #8 Apr 17 2020 03:04:33 %S A031236 0,5,15,25,35,45,46,49,52,55,58,60,75,90,105,120,121,124,127,130,133, %T A031236 135,150,165,180,195,196,199,202,205,208,210,225,240,255,270,271,274, %U A031236 277,280,283,285,300,315,330,345,346,347,350,351 %N A031236 Position of n-th 0 in A031235. %K A031236 nonn %O A031236 1,2 %A A031236 _Clark Kimberling_ %E A031236 a(1)=0 inserted for consistency with change in A031235 by _Sean A. Irvine_, Apr 17 2020