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A243391 Number of isomorphism classes of connected 3-regular loopless multigraphs with n vertices and with semi-edges allowed. 7
1, 3, 4, 12, 22, 68, 166, 534, 1589, 5464, 18579, 68320, 255424, 1000852, 4018156, 16671976, 70890940, 309439942, 1381815168, 6310880471, 29428287639, 140012980007, 678970863717, 3353545264060, 16857749613964, 86191265140699, 447951112379963, 2365177154077186 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(n) is also the number of isomorphism classes of connected loopless multigraphs with n vertices of degree 3 or less. - Andrew Howroyd, Mar 20 2020
LINKS
G. Brinkmann, N. Van Cleemput, T.Pisanski, Generation of various classes of trivalent graphs, Theoretical Computer Science 502, 2013, pp.16-29.
CROSSREFS
Column k=3 of A334546.
Sequence in context: A295948 A129922 A005221 * A000206 A368031 A240737
KEYWORD
nonn
AUTHOR
Nico Van Cleemput, Jun 04 2014
EXTENSIONS
a(23)-a(28) from Andrew Howroyd, Mar 20 2020
STATUS
approved

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Last modified March 29 09:32 EDT 2024. Contains 371268 sequences. (Running on oeis4.)