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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

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

A031148 as a simple table

n a(n)
1 2
2 1
3 2
4 5
5 14
6 43
7 138
8 455
9 1540
10 5305
11 18546
12 65616
13 234546
14 845683
15 3072350
16 11235393
17 41326470
18 152793376
19 567518950
20 2116666670
21 7924062430
22 29765741831
23 112157686170
24 423809991041
25 1605622028100

[2,1,2,5,14,43,138,455,1540,5305,18546,65616,
 234546,845683,3072350,11235393,41326470,152793376,
 567518950,2116666670,7924062430,29765741831,
 112157686170,423809991041,1605622028100]

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 16 09:06 EST 2019. Contains 330020 sequences. (Running on oeis4.)