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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 53 |
| 5 | 917 |
| 6 | 22617 |
| 7 | 735033 |
| 8 | 29953065 |
| 9 | 1479692909 |
| 10 | 86472860573 |
| 11 | 5868283305245 |
| 12 | 455754185294737 |
| 13 | 40032598733260945 |
| 14 | 3938398783862213521 |
| 15 | 430402127790139060725 |
| 16 | 51882414924375353368677 |
| 17 | 6856582955062676722110885 |
| 18 | 988136808489380086666701225 |
[1,1,5,53,917,22617,735033,29953065,1479692909, 86472860573,5868283305245,455754185294737, 40032598733260945,3938398783862213521, 430402127790139060725,51882414924375353368677, 6856582955062676722110885, 988136808489380086666701225] |