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A215858 Number of simple labeled graphs on n nodes with exactly 8 connected components that are trees or cycles. 3
1, 36, 1110, 31680, 904299, 26603148, 821278744, 26864874465, 935625630797, 34750489933016, 1375999952017938, 57998361908305494, 2596646585329104847, 123180358220543885268, 6175880603945440333627, 326438846760992348696038, 18147404450341079958539275 (list; graph; refs; listen; history; text; internal format)
OFFSET

8,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 8..150

EXAMPLE

a(9) = 36: each graph has one 2-node tree and 7 1-node trees and C(9,2) = 36.

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)*

      `if`(i<2, 1, i!/2 +(i+1)^(i-1)), i=0..n-k)))

    end:

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

seq(a(n), n=8..25);

CROSSREFS

Column k=8 of A215861.

The unlabeled version is A215988.

Sequence in context: A000809 A151584 A233085 * A103278 A004294 A075760

Adjacent sequences:  A215855 A215856 A215857 * A215859 A215860 A215861

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Aug 26 2012

STATUS

approved

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Last modified March 30 05:55 EDT 2020. Contains 333119 sequences. (Running on oeis4.)