|
Search: id:A001778
|
|
|
| A001778 |
|
Lah numbers: n!C(n-1,5)/6!.
(Formerly M5279 N2297)
|
|
+0
4
|
|
| 1, 42, 1176, 28224, 635040, 13970880, 307359360, 6849722880, 155831195520, 3636061228800, 87265469491200, 2157837063782400, 55024845126451200, 1447576694865100800, 39291367432052736000, 1100158288097476608000
(list; graph; listen)
|
|
|
OFFSET
|
6,2
|
|
|
REFERENCES
|
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 156.
J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 44.
|
|
FORMULA
|
E.g.f.: ((x/(1-x))^6)/6!.
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)^n*f(n,6,-6), (n>=6). [From Milan R. Janjic (agnus(AT)blic.net), Mar 01 2009]
|
|
PROGRAM
|
(Other) sage: [binomial(n, 6)*factorial (n-1)/factorial (5) for n in xrange(6, 22)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 07 2009]
|
|
CROSSREFS
|
Column 6 of A008297.
Column m=6 of unsigned triangle A111596.
Sequence in context: A016094 A004361 A004373 this_sequence A111780 A075922 A077123
Adjacent sequences: A001775 A001776 A001777 this_sequence A001779 A001780 A001781
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com).
|
|
EXTENSIONS
|
More terms from Christian G. Bower (bowerc(AT)usa.net), Dec 18 2001
|
|
|
Search completed in 0.002 seconds
|
