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 A102171 #15 Jul 31 2021 14:28:11 %S A102171 5,11,24,33,57,64,71,72,116,126,141,174,210,311,334,370,441,480,574 %N A102171 Iccanobirt semiprime indices (1 of 15): Indices of semiprime numbers in A102111. %F A102171 A102111(a(n)) = A102191(n). %Y A102171 Cf. A001358, A102111, A102172-A102185. %K A102171 nonn,more,less,base %O A102171 1,1 %A A102171 _Jonathan Vos Post_ and _Ray Chandler_, Dec 31 2004 %E A102171 a(13) from _Robert Price_, Nov 07 2018 %E A102171 Offset changed to 1 and a(14)-a(19) from _Jinyuan Wang_, Jul 31 2021