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A240684 Number of forests with n labeled nodes and 7 trees. 3
1, 28, 630, 14070, 331485, 8411634, 231354123, 6899167275, 222569372025, 7741879425280, 289297137120992, 11570476164077376, 493535471267193810, 22376155441920000000, 1074961750207964923710, 54561107576767408522752, 2918071167402563863036269 (list; graph; refs; listen; history; text; internal format)
OFFSET

7,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 7..200

FORMULA

a(n) = n^(n-14) * (n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(n^6 + 51*n^5 + 1385*n^4 + 24885*n^3 + 303766*n^2 + 2333976*n + 8648640)/46080. - Vaclav Kotesovec, Sep 06 2014

MAPLE

T:= proc(n, m) option remember; `if`(n<0, 0, `if`(n=m, 1,

      `if`(m<1 or m>n, 0, add(binomial(n-1, j-1)*j^(j-2)*

       T(n-j, m-1), j=1..n-m+1))))

    end:

a:= n-> T(n, 7):

seq(a(n), n=7..30);

MATHEMATICA

Table[n^(n-14) * (n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(n^6 + 51*n^5 + 1385*n^4 + 24885*n^3 + 303766*n^2 + 2333976*n + 8648640)/46080, {n, 7, 25}] (* Vaclav Kotesovec, Sep 06 2014 *)

CROSSREFS

Column m=7 of A105599. A diagonal of A138464.

Sequence in context: A283096 A089908 A038121 * A184329 A070310 A309804

Adjacent sequences:  A240681 A240682 A240683 * A240685 A240686 A240687

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Apr 10 2014

STATUS

approved

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Last modified January 29 16:58 EST 2020. Contains 331347 sequences. (Running on oeis4.)