A120667 Number of n-node labeled bipartite graphs without isolated nodes.
1, 0, 1, 3, 22, 225, 3421, 73668, 2222977, 93033615, 5393456986, 433396737873, 48429436851577, 7548123580987080, 1646092439020192801, 503469306031901522043, 216430661498688457821022, 130959358877474026010486145, 111687660283090149155082836341
Offset: 0
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..60
Crossrefs
Cf. A047864.
Programs
-
Maple
a:= n-> coeff (series (sqrt (add (exp (x*(2^k-2)) *x^k/k!, k=0..n)), x, n+1), x, n)*n!: seq (a(n), n=0..20); # Alois P. Heinz, Sep 12 2008
Formula
E.g.f.: sqrt( e.g.f. for A052332 ) = sqrt(Sum_{n>=0} exp(x*(2^n-2)) * x^n/n!).
Extensions
More terms from Alois P. Heinz, Sep 12 2008