login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A018561
as a simple table
n
a(n)
1
1
2
2
3
3
4
4
5
6
6
12
7
53
8
106
9
159
10
212
11
318
12
636
[1,2,3,4,6,12,53,106,159,212,318,636]