A006713 Number of 3-edge-colored connected trivalent graphs with 2n labeled nodes. (Formerly M4310)

6, 480, 196560, 149869440, 208166112000, 470619551001600, 1622357050938624000, 8100931274981056512000, 56279222605087617687552000, 526611567858781597240688640000, 6462027944190599588931310387200000, 101691538301880025620001692844032000000

Offset

2,1

References

R. C. Read, Some Enumeration Problems in Graph Theory. Ph.D. Dissertation, Department of Mathematics, Univ. London, 1958.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Andrew Howroyd, Table of n, a(n) for n = 2..50

R. C. Read, Letter to N. J. A. Sloane, Feb 04 1971 (gives initial terms of this sequence)

Crossrefs

Cf. A006712 (for not necessarily connected graphs), A248362 (for the incorrect values). See also A002830, A002831, A002851.

Sequence in context: A269761 A229503 A318634 * A248362 A006712 A248361

Adjacent sequences: A006710 A006711 A006712 * A006714 A006715 A006716

Keyword

nonn

Author

N. J. A. Sloane

Extensions

a(5)-a(6) corrected and a(7)-a(10) from Sean A. Irvine, Oct 05 2014

Terms a(11) and beyond from Andrew Howroyd, Dec 18 2017

Status

approved