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 A107278 #12 May 24 2019 17:32:56 %S A107278 1,4,17,60,209,685,2204,6913,21387,65241,197104,590284,1755804, %T A107278 5191723,15276610,44761350,130682371,380337474,1103927291,3196494453 %N A107278 Number of spiro bicyclic skeletons with n carbon atoms. %C A107278 See Parks et al. for precise definition. Sequence is last column of table III. %H A107278 Camden A. Parks and James B. Hendrickson, <a href="https://dokumen.tips/documents/enumeration-of-monocyclic-and-bicyclic-carbon-skeletons.html">Enumeration of monocyclic and bicyclic carbon skeletons</a>, J. Chem. Inf. Comput. Sci., vol. 31, 334-339 (1991). %Y A107278 Table III of the Parks et al. reference has 4 sequences: A121158, A121159, A121160 and this sequence. %K A107278 nonn %O A107278 6,2 %A A107278 _N. J. A. Sloane_, Sep 10 2006 %E A107278 Incorrect g.f. removed by _Georg Fischer_, May 24 2019