%I #14 Mar 21 2020 21:27:05
%S 2,5,7,22,43,141,373,1270,4053,14671,52826,203289,795581,3241367,
%T 13504130,57904671,253856990,1139231977,5219113084,24401837085,
%U 116278408069,564380686932,2787884851040,14007277302822,71538337097031,371197207327709,1955833646495247,10459788214042492
%N Number of isomorphism classes of connected 3-regular multigraphs with n vertices and with loops and semi-edges allowed.
%C a(n) is also the number of isomorphism classes of connected multigraphs with n vertices of degree 3 or less and with loops allowed. - _Andrew Howroyd_, Mar 21 2020
%H G. Brinkmann, N. Van Cleemput, T. Pisanski, <a href="http://dx.doi.org/10.1016/j.tcs.2012.01.018">Generation of various classes of trivalent graphs</a>, Theoretical Computer Science 502, 2013, pp.16-29.
%Y Cf. A000421, A005967, A243391, A243392, A243393, A243394.
%K nonn
%O 1,1
%A _Nico Van Cleemput_, Jun 04 2014
%E a(23)-a(28) from _Andrew Howroyd_, Mar 21 2020