The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 21 |
| 2 | 149 |
| 3 | 1071 |
| 4 | 7793 |
| 5 | 57351 |
| 6 | 426449 |
| 7 | 3200631 |
| 8 | 24221633 |
| 9 | 184649031 |
| 10 | 1416683249 |
| 11 | 10930058391 |
| 12 | 84737546273 |
| 13 | 659705518311 |
| 14 | 5154633748049 |
| 15 | 40402118583351 |
| 16 | 317529017187713 |
| 17 | 2501356987117191 |
| 18 | 19744372064060849 |
| 19 | 156123443001239511 |
[3,21,149,1071,7793,57351,426449,3200631,24221633, 184649031,1416683249,10930058391,84737546273, 659705518311,5154633748049,40402118583351, 317529017187713,2501356987117191, 19744372064060849,156123443001239511] |