A007169 Number of Q-graphs rooted at a polygon.

0, 1, 2, 8, 43, 283, 1946, 14010, 103292, 776784, 5931402, 45870248, 358501321, 2827227425, 22469524972, 179785568562, 1447059691048, 11708296894260, 95176461591230, 776935668014674, 6366225809581766, 52344041948585714

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

References

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

Links

• R. C. Read, On the enumeration of a class of plane multigraphs, Aequat. Math. 31 (1986) no 1, 47-63.

Crossrefs

Cf. A003168.

Formula

G.f. Sum_{r >= 2} Z(C_{2*r}; B(x)) where Z(C_{2*r}) is the cycle index of the cyclic group C_{2*r} and B(x) is the g.f. for A003168. - Sean A. Irvine, Nov 07 2017

Extensions

a(9) corrected and more terms from Sean A. Irvine, Nov 07 2017