login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A001183
as a simple table
n
a(n)
1
0
2
2
3
2
4
18
5
66
6
374
7
1694
8
9822
9
51698
[0,2,2,18,66,374,1694,9822,51698]