login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A271599
as a simple table
n
a(n)
0
1
1
5
2
20
3
65
4
225
5
796
6
3220
7
11880
8
47172
9
188004
10
747464
11
2982848
12
11909008
13
47634836
14
190514480
15
761884472
[1,5,20,65,225,796,3220,11880,47172,188004,747464, 2982848,11909008,47634836,190514480,761884472]