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

Author

Alois P. Heinz, Aug 23 2012

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 7..170

Crossrefs

Column k=7 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, 7):
seq (a(n), n=7..25);