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A111597 Lah numbers: n!*binomial(n-1,6)/7!. 3
1, 56, 2016, 60480, 1663200, 43908480, 1141620480, 29682132480, 779155977600, 20777492736000, 565147802419200, 15721384321843200, 448059453172531200, 13097122477350912000, 392913674320527360000, 12101741169072242688000 (list; graph; refs; listen; history; text; internal format)
OFFSET

7,2

REFERENCES

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 156.

J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 44.

LINKS

Table of n, a(n) for n=7..22.

FORMULA

E.g.f. ((x/(1-x))^7)/7!.

a(n)= (n!/7!)*binomial(n-1, 7-1).

If we define f(n,i,x)= sum(sum(binomial(k,j)*stirling1(n,k)*stirling2(j,i)*x^(k-j),j=i..k),k=i..n) then a(n+1)=(-1)^n*f(n,6,-8), (n>=6). [From Milan Janjic, Mar 01 2009]

MATHEMATICA

k = 7; a[n_] := n!*Binomial[n-1, k-1]/k!; Table[a[n], {n, k, 22}]  (* Jean-Fran├žois Alcover, Jul 09 2013 *)

CROSSREFS

Column 7 of A008297 and unsigned A111596. Column 6: A001778.

Sequence in context: A004375 A103726 A004387 * A111781 A221398 A280803

Adjacent sequences:  A111594 A111595 A111596 * A111598 A111599 A111600

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang, Aug 23 2005

STATUS

approved

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Last modified February 24 09:40 EST 2020. Contains 332209 sequences. (Running on oeis4.)