The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 81 |
| 3 | 261 |
| 4 | 1269 |
| 5 | 5139 |
| 6 | 22509 |
| 7 | 95265 |
| 8 | 409239 |
| 9 | 1746639 |
| 10 | 7475751 |
| 11 | 31957515 |
| 12 | 136685781 |
| 13 | 584484003 |
| 14 | 2499573411 |
| 15 | 10689072525 |
| 16 | 45711185121 |
| 17 | 195479542125 |
| 18 | 835952734845 |
| 19 | 3574879817931 |
| 20 | 15287675934645 |
| 21 | 65376453864249 |
[9,81,261,1269,5139,22509,95265,409239,1746639, 7475751,31957515,136685781,584484003,2499573411, 10689072525,45711185121,195479542125,835952734845, 3574879817931,15287675934645,65376453864249] |