login
This site is supported by donations to The OEIS Foundation.

 

Logo

"Email this user" was broken Aug 14 to 9am Aug 16. If you sent someone a message in this period, please send it again.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A133068 Number of surjections from an n-element set to an eight-element set. 0
40320, 1451520, 30240000, 479001600, 6411968640, 76592355840, 843184742400, 8734434508800, 86355926616960, 823172919528960, 7621934141203200, 68937160460313600, 611692004959217280, 5342844138794426880 (list; graph; refs; listen; history; text; internal format)
OFFSET

8,1

LINKS

Table of n, a(n) for n=8..21.

Index entries for linear recurrences with constant coefficients, signature (36,-546,4536,-22449,67284,-118124,109584,-40320).

FORMULA

a(n) = sum((-1)^(8-k)*C(8,k)*k^n) with n>=8 and k=8,7,...,1.

a(n) = A049434(n) * 8!. - Max Alekseyev, Nov 13 2009

G.f.: 40320*x^8/((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(7*x-1)*(8*x-1)). - Colin Barker, Oct 25 2012

CROSSREFS

Cf. A000918, A000919, A000920, A001117, A001118, A135456.

Sequence in context: A179734 A061123 A029576 * A254081 A228911 A213878

Adjacent sequences:  A133065 A133066 A133067 * A133069 A133070 A133071

KEYWORD

nonn,easy

AUTHOR

Mohamed Bouhamida (bhmd95(AT)yahoo.fr), Dec 16 2007; Dec 21 2007

EXTENSIONS

Edited by N. J. A. Sloane, Jul 12 2008 at the suggestion of R. J. Mathar

More terms from Max Alekseyev, Nov 13 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified August 20 15:02 EDT 2017. Contains 290835 sequences.