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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 15 |
| 2 | 131 |
| 3 | 1613 |
| 4 | 25097 |
| 5 | 461105 |
| 6 | 9483041 |
| 7 | 209175233 |
| 8 | 4802367617 |
| 9 | 112660505345 |
| 10 | 2672797504001 |
| 11 | 63775070743553 |
| 12 | 1526140298561537 |
| 13 | 36573850636201985 |
| 14 | 877130337148149761 |
| 15 | 21043423870122115073 |
| 16 | 504949726500343545857 |
| 17 | 12117684104978986369025 |
[1,15,131,1613,25097,461105,9483041,209175233, 4802367617,112660505345,2672797504001, 63775070743553,1526140298561537,36573850636201985, 877130337148149761,21043423870122115073, 504949726500343545857,12117684104978986369025] |