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!)

A002864 as a simple table

n a(n)
1 0
2 0
3 1
4 1
5 2
6 3
7 7
8 18
9 41
10 123
11 367
12 1288
13 4878
14 19536
15 85263
16 379799
17 1769979
18 8400285
19 40619385
20 199631989
21 990623857
22 4976016485
23 25182878921

[0,0,1,1,2,3,7,18,41,123,367,1288,4878,19536,
 85263,379799,1769979,8400285,40619385,199631989,
 990623857,4976016485,25182878921]

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 12 07:31 EST 2019. Contains 329948 sequences. (Running on oeis4.)