A007110 - OEIS

%I M5163 #11 Dec 19 2021 00:11:55

%S 0,0,0,0,0,24,570,27900,1827630,152031600,15453811800,1884214710000,

%T 271711218933000,45788138466285600,8922341314806519600,

%U 1991726163596104135200,505133470313552174094000

%N Number of connected labeled 2-regular oriented graphs with n nodes.

%D R. W. Robinson, personal communication.

%D R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1982.

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

%H R. W. Robinson, <a href="/A007110/b007110.txt">Table of n, a(n) for n = 0..48</a>

%K nonn,nice

%O 0,6

%A _N. J. A. Sloane_