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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 881 |
| 3 | 13322 |
| 4 | 261354 |
| 5 | 5692727 |
| 6 | 114153198 |
| 7 | 2324267560 |
| 8 | 47816866681 |
| 9 | 977475485051 |
| 10 | 19995290562764 |
| 11 | 409424488722963 |
| 12 | 8379383231723319 |
| 13 | 171496319503906722 |
| 14 | 3510231619208724703 |
| 15 | 71845872758808645456 |
[21,881,13322,261354,5692727,114153198,2324267560, 47816866681,977475485051,19995290562764, 409424488722963,8379383231723319, 171496319503906722,3510231619208724703, 71845872758808645456] |