A243392 Number of isomorphism classes of connected 3-regular simple graphs of order 2n with loops and semi-edges allowed.

2, 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

Offset

1,1

Links

Table of n, a(n) for n=1..28.

G. Brinkmann, N. Van Cleemput, T. Pisanski, Generation of various classes of trivalent graphs, Theoretical Computer Science 502, 2013, pp.16-29.

Crossrefs

Differs from A243391 only in the first term.

Sequence in context: A295620 A007499 A117555 * A239943 A295754 A059810

Adjacent sequences: A243389 A243390 A243391 * A243393 A243394 A243395

Keyword

nonn

Author

Nico Van Cleemput, Jun 04 2014

Extensions

a(23)-a(28) from Andrew Howroyd, May 06 2021

Status

approved