n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 18 |
4 | 86 |
5 | 427 |
6 | 2180 |
7 | 11373 |
8 | 60380 |
9 | 325259 |
10 | 1773842 |
11 | 9776637 |
12 | 54380144 |
13 | 304905223 |
14 | 1721650832 |
15 | 9782051362 |
16 | 55888463214 |
17 | 320898932595 |
18 | 1850762866662 |
19 | 10717217871255 |
20 | 62287285235230 |
21 | 363212668363520 |
22 | 2124430957852380 |
[1,1,4,18,86,427,2180,11373,60380,325259,1773842, 9776637,54380144,304905223,1721650832,9782051362, 55888463214,320898932595,1850762866662, 10717217871255,62287285235230,363212668363520, 2124430957852380] |