%I M4310 #19 Dec 18 2017 22:45:05

%S 6,480,196560,149869440,208166112000,470619551001600,

%T 1622357050938624000,8100931274981056512000,

%U 56279222605087617687552000,526611567858781597240688640000,6462027944190599588931310387200000,101691538301880025620001692844032000000

%N Number of 3-edge-colored connected trivalent graphs with 2n labeled nodes.

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

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

%H Andrew Howroyd, <a href="/A006713/b006713.txt">Table of n, a(n) for n = 2..50</a>

%H R. C. Read, <a href="/A002831/a002831.pdf">Letter to N. J. A. Sloane, Feb 04 1971</a> (gives initial terms of this sequence)

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

%K nonn

%O 2,1

%A _N. J. A. Sloane_

%E a(5)-a(6) corrected and a(7)-a(10) from _Sean A. Irvine_, Oct 05 2014

%E Terms a(11) and beyond from _Andrew Howroyd_, Dec 18 2017