A215768 Number of undirected labeled graphs on n nodes with exactly 8 cycle graphs as connected components.

1, 36, 750, 12540, 195459, 3057912, 49471708, 835659825, 14779601837, 273850769192, 5313937212402, 107889695430426, 2289283137461287, 50700986253094800, 1170451253565199375, 28127697404018935030, 702741240223958509651, 18230243438652550293450

Offset

8,2

Links

Alois P. Heinz, Table of n, a(n) for n = 8..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, 8):
seq (a(n), n=8..30);

Crossrefs

Column k=8 of A215771.

Sequence in context: A089909 A049434 A327509 * A320821 A144941 A036084

Adjacent sequences: A215765 A215766 A215767 * A215769 A215770 A215771

Keyword

nonn

Author

Alois P. Heinz, Aug 23 2012

Status

approved