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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 149 |
| 5 | 2016 |
| 6 | 34447 |
| 7 | 692224 |
| 8 | 15986889 |
| 9 | 420544000 |
| 10 | 12494098331 |
| 11 | 414681513984 |
| 12 | 15201740343517 |
| 13 | 609446038061056 |
| 14 | 26511336043734375 |
| 15 | 1243650774790045696 |
| 16 | 62591481040666342673 |
| 17 | 3364694927903114919936 |
| 18 | 192423068815578523022899 |
| 19 | 11665229364232192000000000 |
[1,1,3,16,149,2016,34447,692224,15986889, 420544000,12494098331,414681513984,15201740343517, 609446038061056,26511336043734375, 1243650774790045696,62591481040666342673, 3364694927903114919936,192423068815578523022899, 11665229364232192000000000] |