A294724 Number of Q graphs with 2*n vertices rooted at an internal edge.

0, 0, 0, 1, 11, 96, 785, 6283, 49987, 397768, 3174084, 25426290, 204538114, 1652327820, 13402442651, 109129475455, 891793354235, 7312118010384, 60141701374424, 496095022537998, 4103183675407098, 34022136992384720

Offset: 1

Author

Sean A. Irvine, Nov 07 2017

Keywords

• nonn

Links

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

Crossrefs

Cf. A003168, A003169.

Formula

G.f.: P(x) * (B(x) - x)^2 where P(x) is the g.f. for A003169 and B(x) is the g.f. for A003168.