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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 15 |
| 4 | 176 |
| 5 | 2905 |
| 6 | 61536 |
| 7 | 1592703 |
| 8 | 48706048 |
| 9 | 1718376561 |
| 10 | 68702272000 |
| 11 | 3069734553743 |
| 12 | 151592011714560 |
| 13 | 8198710703202825 |
| 14 | 481965222651551744 |
| 15 | 30598546651134134655 |
| 16 | 2086474763912627879936 |
| 17 | 152083996930329322871521 |
| 18 | 11800530001358902191587328 |
| 19 | 971113004536128839898536079 |
[1,2,15,176,2905,61536,1592703,48706048, 1718376561,68702272000,3069734553743, 151592011714560,8198710703202825, 481965222651551744,30598546651134134655, 2086474763912627879936,152083996930329322871521, 11800530001358902191587328, 971113004536128839898536079] |