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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 111 |
| 3 | 928 |
| 4 | 7356 |
| 5 | 56436 |
| 6 | 423579 |
| 7 | 3129552 |
| 8 | 22851201 |
| 9 | 165333648 |
| 10 | 1187526564 |
| 11 | 8478925056 |
| 12 | 60241049848 |
| 13 | 426221826564 |
| 14 | 3004932019443 |
| 15 | 21120318379488 |
| 16 | 148048546150899 |
| 17 | 1035347613355212 |
| 18 | 7225423763357031 |
| 19 | 50330772078599808 |
| 20 | 350009710750032624 |
| 21 | 2430378171200375472 |
[1,12,111,928,7356,56436,423579,3129552,22851201, 165333648,1187526564,8478925056,60241049848, 426221826564,3004932019443,21120318379488, 148048546150899,1035347613355212,7225423763357031, 50330772078599808,350009710750032624, 2430378171200375472] |