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 A123356 #8 Jul 26 2019 06:17:08 %S A123356 1,4,50,805,15218,326053,7736092,199806100 %N A123356 Kekulé numbers for certain benzenoids (see the Cyvin-Gutman book for details). %H A123356 Cyvin S.J., Gutman I. (1988) <a href="https://doi.org/10.1007/978-3-662-00892-8_11">Classes of Basic Benzenoids (III)</a>. In: Kekulé Structures in Benzenoid Hydrocarbons. Lecture Notes in Chemistry, vol 46. Springer, Berlin, Heidelberg (see p. 188) %K A123356 nonn %O A123356 0,2 %A A123356 _N. J. A. Sloane_, Oct 10 2006