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Number of isomorphism classes of connected 4-regular loopless multigraphs of order n.
10

%I #29 Mar 17 2020 20:54:22

%S 1,0,1,1,3,6,19,50,204,832,4330,25227,171886,1303725,10959478,

%T 100230117,989280132,10455393155,117701173970,1405165683359,

%U 17726785643045,235585551038117,3289367315407521,48136794098893837,736721822918719557,11768987500655142988

%N Number of isomorphism classes of connected 4-regular loopless multigraphs of order n.

%C Initial terms computed using software at http://users.cecs.anu.edu.au/~bdm/nauty/

%C Obtained from A129418 by an inverse Euler transform. - _R. J. Mathar_, Mar 09 2019

%H Brendan McKay and Adolfo Piperno, <a href="http://pallini.di.uniroma1.it">Nauty and Traces</a>

%o (nauty/bash) geng -c -d1 ${n} -q | multig -r4 -u # _Natan Arie Consigli_, Jun 05 2017

%Y Column k=4 of A328682.

%Y Cf. A129418, A085549, A000421, A129419, A129421, A129423, A129425, A328682.

%K nonn

%O 0,5

%A _Brendan McKay_, Apr 15 2007

%E a(0)-a(1) prepended by _Natan Arie Consigli_, Jun 05 2017

%E a(18)-a(25) from _Andrew Howroyd_, Mar 17 2020