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 A006647 M2586 #20 Jul 08 2025 16:51:20 %S A006647 1,1,3,6,15,33,83,202,527,1377,3744,10335,29297,84396,248034,740289, %T A006647 2245094,6904206,21522973,67936799,217026480,701159919,2289925258, %U A006647 7556363054,25184139149,84743377436,287815771822,986345040471,3409869008578 %N A006647 Number of graphs with n nodes, n-2 edges and no isolated vertices. %D A006647 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A006647 W. L. Kocay, <a href="http://www.combinatorialmath.ca/G&G/articles/algebraofsubgraphs.pdf">Some new methods in reconstruction theory</a>, pp. 89 - 114 of Combinatorial Mathematics IX. Proc. Ninth Australian Conference (Brisbane, August 1981). Ed. E. J. Billington, S. Oates-Williams and A. P. Street. Lecture Notes Math., 952. Springer-Verlag, 1982. %F A006647 a(n) = A001430(n) - A001433(n - 1). - _Sean A. Irvine_, Jun 05 2017 %Y A006647 Cf. A001430, A001433. %K A006647 nonn %O A006647 4,3 %A A006647 _N. J. A. Sloane_ %E A006647 More terms from _Vladeta Jovovic_, Mar 02 2008 %E A006647 More terms from _Sean A. Irvine_, Jun 05 2017