login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A218209
as a simple table
n
a(n)
1
2
2
1
3
3
4
4
5
12
6
31
7
86
8
230
9
681
10
1934
11
5634
12
15772
[2,1,3,4,12,31,86,230,681,1934,5634,15772]