| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 11 |
| 2 | 69 |
| 3 | 521 |
| 4 | 4113 |
| 5 | 32801 |
| 6 | 262209 |
| 7 | 2097281 |
| 8 | 16777473 |
| 9 | 134218241 |
| 10 | 1073742849 |
| 11 | 8589936641 |
| 12 | 68719480833 |
| 13 | 549755822081 |
| 14 | 4398046527489 |
| 15 | 35184372121601 |
| 16 | 281474976776193 |
| 17 | 2251799813816321 |
| 18 | 18014398509744129 |
| 19 | 144115188076380161 |
[3,11,69,521,4113,32801,262209,2097281,16777473, 134218241,1073742849,8589936641,68719480833, 549755822081,4398046527489,35184372121601, 281474976776193,2251799813816321, 18014398509744129,144115188076380161] |