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 A320995 #11 Jan 28 2020 00:32:40 %S A320995 1,0,5,136,24162,29488085,286615837574,21717610066598371, %T A320995 12980514969049888065118,62082684164458190567999459967, %U A320995 2405195234525224724112302276711929089,762399076229936058613587754015434541854738381 %N A320995 Number of connected self-dual nets with 2n nodes. %H A320995 Andrew Howroyd, <a href="/A320995/b320995.txt">Table of n, a(n) for n = 0..40</a> %H A320995 Edward A. Bender and E. Rodney Canfield, <a href="https://doi.org/10.1016/0095-8956(83)90040-0">Enumeration of connected invariant graphs</a>, Journal of Combinatorial Theory, Series B 34.3 (1983): 268-278. See p. 275. %H A320995 Andrew Howroyd, <a href="/A320995/a320995.txt">PARI Program</a> %F A320995 a(2*n-1) = b(2*n-1) - A320489(2*n-1)/2, a(2*n) = b(2*n) - (A320489(2*n)-a(n))/2 where b is the Inverse Euler transform of A004107. - _Andrew Howroyd_, Jan 27 2020 %o A320995 (PARI) \\ See link for program. %o A320995 A320995seq(15) \\ _Andrew Howroyd_, Jan 27 2020 %Y A320995 Cf. A004103 (not necessarily connected nets), A004107 (self-dual), A320489 (connected nets). %K A320995 nonn %O A320995 0,3 %A A320995 _N. J. A. Sloane_, Oct 26 2018 %E A320995 a(0)=1 prepended and terms a(7) and beyond from _Andrew Howroyd_, Jan 26 2020