The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 339 |
| 3 | 1426 |
| 4 | 6545 |
| 5 | 30727 |
| 6 | 148966 |
| 7 | 734805 |
| 8 | 3679063 |
| 9 | 18601074 |
| 10 | 94728601 |
| 11 | 484797943 |
| 12 | 2489729974 |
| 13 | 12816761181 |
| 14 | 66088527271 |
| 15 | 341168095114 |
| 16 | 1762603785057 |
| 17 | 9111229406855 |
| 18 | 47115466594414 |
| 19 | 243704127371685 |
| 20 | 1260784775294295 |
[81,339,1426,6545,30727,148966,734805,3679063, 18601074,94728601,484797943,2489729974, 12816761181,66088527271,341168095114, 1762603785057,9111229406855,47115466594414, 243704127371685,1260784775294295] |