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 A121330 #3 Mar 30 2012 16:50:30 %S A121330 0,0,0,8,9,53,251,1053,4078,14945,52586,179411,597480,1951618,6274858, %T A121330 19912475,62497879,194330213,599408935,1836028197,5589730484 %N A121330 Number of bridged bicyclic skeletons with n carbon atoms (see Parks et al. for precise definition). %D A121330 Camden A. Parks and James B. Hendrickson, Enumeration of monocyclic and bicyclic carbon skeletons, J. Chem. Inf. Comput. Sci., vol. 31, 334-339 (1991). %K A121330 nonn %O A121330 5,4 %A A121330 _N. J. A. Sloane_, Aug 27 2006