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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 25 |
| 3 | 254 |
| 4 | 2844 |
| 5 | 34031 |
| 6 | 426498 |
| 7 | 5526399 |
| 8 | 73433377 |
| 9 | 995167783 |
| 10 | 13701794657 |
| 11 | 191122323160 |
| 12 | 2695092314319 |
| 13 | 38357425655599 |
| 14 | 550268824751092 |
| 15 | 7948720164361366 |
| 16 | 115517358604881329 |
| 17 | 1687796954715824015 |
| 18 | 24777722054035138573 |
| 19 | 365305177280838473896 |
[1,3,25,254,2844,34031,426498,5526399,73433377, 995167783,13701794657,191122323160,2695092314319, 38357425655599,550268824751092,7948720164361366, 115517358604881329,1687796954715824015, 24777722054035138573,365305177280838473896] |