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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 23 |
| 4 | 416 |
| 5 | 7344 |
| 6 | 134613 |
| 7 | 2620379 |
| 8 | 54636792 |
| 9 | 1223392968 |
| 10 | 29409134545 |
| 11 | 757686550455 |
| 12 | 20870680635528 |
| 13 | 612964613117960 |
| 14 | 19140704352872949 |
| 15 | 633710701752022635 |
| 16 | 22185391759982205904 |
| 17 | 819180275431111135536 |
| 18 | 31826528430233802890049 |
| 19 | 1298154677953792936043447 |
| 20 | 55473817874169725876166480 |
[1,23,416,7344,134613,2620379,54636792,1223392968, 29409134545,757686550455,20870680635528, 612964613117960,19140704352872949, 633710701752022635,22185391759982205904, 819180275431111135536,31826528430233802890049, 1298154677953792936043447, 55473817874169725876166480] |