A215768 - OEIS

%I #5 Aug 23 2012 21:06:44

%S 1,36,750,12540,195459,3057912,49471708,835659825,14779601837,

%T 273850769192,5313937212402,107889695430426,2289283137461287,

%U 50700986253094800,1170451253565199375,28127697404018935030,702741240223958509651,18230243438652550293450

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

%H Alois P. Heinz, <a href="/A215768/b215768.txt">Table of n, a(n) for n = 8..170</a>

%p T:= proc(n, k) option remember; `if`(k<0 or k>n, 0, `if`(n=0, 1,

%p       add(binomial(n-1, i)*T(n-1-i, k-1)*ceil(i!/2), i=0..n-k)))

%p     end:

%p a:= n-> T(n, 8):

%p seq (a(n), n=8..30);

%Y Column k=8 of A215771.

%K nonn

%O 8,2

%A _Alois P. Heinz_, Aug 23 2012