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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 67 |
| 4 | 741 |
| 5 | 8909 |
| 6 | 113107 |
| 7 | 1492103 |
| 8 | 20251945 |
| 9 | 280978681 |
| 10 | 3967031839 |
| 11 | 56811348235 |
| 12 | 823250855181 |
| 13 | 12049087175493 |
| 14 | 177857857845675 |
| 15 | 2644773866954255 |
| 16 | 39581787842355409 |
| 17 | 595745692419162737 |
| 18 | 9011736489133233463 |
| 19 | 136932249972928786387 |
| 20 | 2089082351509217490613 |
[1,1,7,67,741,8909,113107,1492103,20251945, 280978681,3967031839,56811348235,823250855181, 12049087175493,177857857845675,2644773866954255, 39581787842355409,595745692419162737, 9011736489133233463,136932249972928786387, 2089082351509217490613] |