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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 111 |
| 4 | 936 |
| 5 | 7569 |
| 6 | 59940 |
| 7 | 469503 |
| 8 | 3656016 |
| 9 | 28378593 |
| 10 | 219894588 |
| 11 | 1702241487 |
| 12 | 13170376440 |
| 13 | 101870548209 |
| 14 | 787824155988 |
| 15 | 6092161780959 |
| 16 | 47107744223904 |
| 17 | 364251591915201 |
| 18 | 2816463543593580 |
| 19 | 21777259989921327 |
| 20 | 168383822940467784 |
[1,12,111,936,7569,59940,469503,3656016,28378593, 219894588,1702241487,13170376440,101870548209, 787824155988,6092161780959,47107744223904, 364251591915201,2816463543593580, 21777259989921327,168383822940467784] |