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

%I A215768 #5 Aug 23 2012 21:06:44
%S A215768 1,36,750,12540,195459,3057912,49471708,835659825,14779601837,
%T A215768 273850769192,5313937212402,107889695430426,2289283137461287,
%U A215768 50700986253094800,1170451253565199375,28127697404018935030,702741240223958509651,18230243438652550293450
%N A215768 Number of undirected labeled graphs on n nodes with exactly 8 cycle graphs as connected components.
%H A215768 Alois P. Heinz, <a href="/A215768/b215768.txt">Table of n, a(n) for n = 8..170</a>
%p A215768 T:= proc(n, k) option remember; `if`(k<0 or k>n, 0, `if`(n=0, 1,
%p A215768       add(binomial(n-1, i)*T(n-1-i, k-1)*ceil(i!/2), i=0..n-k)))
%p A215768     end:
%p A215768 a:= n-> T(n, 8):
%p A215768 seq (a(n), n=8..30);
%Y A215768 Column k=8 of A215771.
%K A215768 nonn
%O A215768 8,2
%A A215768 _Alois P. Heinz_, Aug 23 2012