A215769 Number of undirected labeled graphs on n nodes with exactly 9 cycle graphs as connected components.

1, 45, 1155, 23265, 425139, 7606599, 138177325, 2587238940, 50238819917, 1014260971581, 21309355619799, 465938970674775, 10598414480600407, 250610854305313887, 6155065643528547592, 156866857683142545246, 4144501278635384568055, 113404466183331483985825

Offset: 9

Author

Alois P. Heinz, Aug 23 2012

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 9..170

Crossrefs

Column k=9 of A215771.

Programs

Maple

T:= proc(n, k) option remember; `if`(k<0 or k>n, 0, `if`(n=0, 1,
      add(binomial(n-1, i)*T(n-1-i, k-1)*ceil(i!/2), i=0..n-k)))
    end:
a:= n-> T(n, 9):
seq (a(n), n=9..30);