A215765 Number of undirected labeled graphs on n nodes with exactly 5 cycle graphs as connected components.

1, 15, 140, 1190, 10857, 109935, 1222210, 14771955, 192855949, 2705536834, 40597839100, 648954464340, 11010645610113, 197646020548569, 3742573587799761, 74560940574685875, 1559079985774886316, 34142131775027937276, 781462189858194371736

Offset: 5

Author

Alois P. Heinz, Aug 23 2012

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 5..170

Crossrefs

Column k=5 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, 5):
seq (a(n), n=5..25);