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 A070217 #12 Aug 15 2020 08:05:44 %S A070217 2,3,5,8,13,17,18,21,33,34,38 %N A070217 Numbers not represented by a known atomic weight as given in Francis W. Aston's Nobel lecture in 1922. %H A070217 Francis W. Aston, <a href="https://www.nobelprize.org/prizes/chemistry/1922/aston/lecture/">Mass spectra and isotopes</a>, Nobel Lecture, December 12, 1922. See p. 18. %Y A070217 Cf. A007656. %K A070217 nonn,fini,full %O A070217 1,1 %A A070217 _Robert G. Wilson v_, May 07 2002 %E A070217 Stripped data to original list on page 18 of Aston's lecture by _Elijah Beregovsky_, Aug 15 2020.