login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A156801
as a simple table
n
a(n)
1
1
2
2
3
4
4
9
5
21
6
64
7
218
8
1068
9
8038
10
114188
11
3493965
12
235176097
[1,2,4,9,21,64,218,1068,8038,114188,3493965, 235176097]