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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)

A117998 as a simple table

n a(n)
0 1
1 6
2 20
3 120
4 272
5 1632
6 5440
7 32640
8 65792
9 394752
10 1315840
11 7895040
12 17895424
13 107372544
14 357908480
15 2147450880
16 4295032832
17 25770196992
18 85900656640
19 515403939840
20 1168248930304
21 7009493581824
22 23364978606080

[1,6,20,120,272,1632,5440,32640,65792,394752,
 1315840,7895040,17895424,107372544,357908480,
 2147450880,4295032832,25770196992,85900656640,
 515403939840,1168248930304,7009493581824,
 23364978606080]

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 December 17 18:04 EST 2014. Contains 252034 sequences.