login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A007648
as a simple table
n
a(n)
1
1
2
3
3
21
4
23
5
842
6
1683
7
3401
8
16839
9
49963
10
60239
11
150940
12
155928
[1,3,21,23,842,1683,3401,16839,49963,60239,150940, 155928]