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 A129418 #23 Jun 02 2025 16:32:11
%S A129418 1,0,1,1,4,7,24,60,240,930,4701,26637,178569,1339529,11187064,
%T A129418 101871881,1002594996,10574095327,118850827173,1417140114336,
%U A129418 17860018997346,237160827107408,3309078044759285,48396906463199522,740331404753448181,11821525310570525197
%N A129418 Number of isomorphism classes of 4-regular loopless multigraphs of order n.
%C A129418 Initial terms computed using software at http://users.cecs.anu.edu.au/~bdm/nauty/
%C A129418 Also number of carbon allotropes satisfying the octet rule, excluding stereoisomers. - _Natan Arie Consigli_, Jun 06 2017
%F A129418 Euler transform of A129417. - _Andrew Howroyd_, Mar 14 2020
%o A129418 (nauty) geng -d1 ${n} -q | multig -r4 -u # _Natan Arie Consigli_, Jun 06 2017
%Y A129418 Column k=4 of A333330.
%Y A129418 Cf. A129417, A129429, A129416, A129420, A129422, A129424, A129426.
%K A129418 nonn
%O A129418 0,5
%A A129418 _Brendan McKay_, Apr 15 2007
%E A129418 a(0)-a(1) by _Natan Arie Consigli_, Jun 06 2017
%E A129418 a(18)-a(25) from _Andrew Howroyd_, Mar 17 2020