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

 

Logo

Many excellent designs for a new banner were submitted. We will use the best of them in rotation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A175430 a(n) = (n-1)! * (n+1)! 2
2, 6, 48, 720, 17280, 604800, 29030400, 1828915200, 146313216000, 14485008384000, 1738201006080000, 248562743869440000, 41758540970065920000, 8142915489162854400000, 1824013069572479385600000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = (Product_(k=1,2,...,n) k*A020725(k)) / n = (Product_(k=1,2,...,n) k*(k+1)) / n.

a(n) = (-1) * A129464(n) = A179442(n) * n. [From Jaroslav Krizek, Jul 22 2010]

LINKS

Table of n, a(n) for n=1..15.

EXAMPLE

a(5) = (5-1)! * (5+1)! = 4! * 6! = 24 * 720 = 17280.

a(5) = ((1*2) * (2*3) * (3*4) * (4*5) * (5*6)) / 5 = 17280.

CROSSREFS

Sequence in context: A052587 A052735 A052717 * A129464 A003053 A113296

Adjacent sequences:  A175427 A175428 A175429 * A175431 A175432 A175433

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, May 10 2010

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified April 23 12:03 EDT 2014. Contains 240919 sequences.