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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 59 |
| 6 | 501 |
| 7 | 3786 |
| 8 | 48337 |
| 9 | 508402 |
| 10 | 6469142 |
| 11 | 81711572 |
| 12 | 2019160542 |
| 13 | 31945830446 |
| 14 | 749115591093 |
| 15 | 15230426073946 |
| 16 | 617313283787616 |
| 17 | 13472047923890487 |
[1,1,1,2,10,59,501,3786,48337,508402,6469142, 81711572,2019160542,31945830446,749115591093, 15230426073946,617313283787616,13472047923890487] |