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

5,2

Links

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

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);

Crossrefs

Column k=5 of A215771.

Sequence in context: A327506 A346955 A346920 * A055903 A320818 A026859

Adjacent sequences: A215762 A215763 A215764 * A215766 A215767 A215768

Keyword

nonn

Author

Alois P. Heinz, Aug 23 2012

Status

approved