A132219 Number of line graphs on n labeled nodes.

1, 2, 8, 66, 774, 11885, 230858, 5512821, 157926273, 5323010347, 207833183972, 9280406921629, 468879370270319, 26561064972285450, 1673867356632729422, 116555375609273658636, 8914259769349445083676, 744876885721366948399627

Offset

1,2

Links

Table of n, a(n) for n=1..18.

Formula

E.g.f.: exp(x/2-x^3/6)*Sum(A020556(n)*(log(1+x)/2)^n/n!, n=0..infinity).

Crossrefs

Cf. A132220 (unlabeled case).

Sequence in context: A100623 A231280 A086594 * A226730 A202553 A023164

Adjacent sequences: A132216 A132217 A132218 * A132220 A132221 A132222

Keyword

nonn

Author

Vladeta Jovovic, Aug 14 2007

Status

approved