The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 61 |
| 3 | 541 |
| 4 | 902 |
| 5 | 4013 |
| 6 | 29411 |
| 7 | 160247 |
| 8 | 660748 |
| 9 | 3071197 |
| 10 | 17079507 |
| 11 | 88199621 |
| 12 | 419285701 |
| 13 | 2063343133 |
| 14 | 10608771290 |
| 15 | 53689192266 |
| 16 | 265848111937 |
| 17 | 1327085663799 |
| 18 | 6701302273037 |
| 19 | 33718513860297 |
| 20 | 168717573787828 |
| 21 | 845811333794914 |
[0,61,541,902,4013,29411,160247,660748,3071197, 17079507,88199621,419285701,2063343133, 10608771290,53689192266,265848111937, 1327085663799,6701302273037,33718513860297, 168717573787828,845811333794914] |