A215767 Number of undirected labeled graphs on n nodes with exactly 7 cycle graphs as connected components.

1, 28, 462, 6300, 82929, 1128204, 16187314, 245722477, 3944372432, 66863837040, 1194908786890, 22468992674310, 443708326841383, 9184432111987960, 198909290886899005, 4499373643453767540, 106128250525908452226, 2606280798870785902866, 66541442123879872392375

Offset

7,2

Links

Alois P. Heinz, Table of n, a(n) for n = 7..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, 7):
seq (a(n), n=7..25);

Crossrefs

Column k=7 of A215771.

Sequence in context: A022752 A000771 A327508 * A079518 A320820 A160060

Adjacent sequences: A215764 A215765 A215766 * A215768 A215769 A215770

Keyword

nonn

Author

Alois P. Heinz, Aug 23 2012

Status

approved