A129417 - OEIS

A129417

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

1, 0, 1, 1, 3, 6, 19, 50, 204, 832, 4330, 25227, 171886, 1303725, 10959478, 100230117, 989280132, 10455393155, 117701173970, 1405165683359, 17726785643045, 235585551038117, 3289367315407521, 48136794098893837, 736721822918719557, 11768987500655142988

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OFFSET

0,5

COMMENTS

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

Obtained from A129418 by an inverse Euler transform. - R. J. Mathar, Mar 09 2019

LINKS

Table of n, a(n) for n=0..25.

Brendan McKay and Adolfo Piperno, Nauty and Traces

PROG

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

CROSSREFS