n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 1 |
3 | 4 |
4 | 17 |
5 | 81 |
6 | 412 |
7 | 2192 |
8 | 12049 |
9 | 67891 |
10 | 390041 |
11 | 2276176 |
12 | 13455356 |
13 | 80402284 |
14 | 484865032 |
15 | 2947107384 |
16 | 18036248337 |
17 | 111046920567 |
18 | 687345582787 |
19 | 4274642610932 |
20 | 26697307240777 |
21 | 167377288848977 |
[0,1,1,4,17,81,412,2192,12049,67891,390041, 2276176,13455356,80402284,484865032,2947107384, 18036248337,111046920567,687345582787, 4274642610932,26697307240777,167377288848977] |