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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 19 |
| 2 | 342 |
| 3 | 6156 |
| 4 | 110808 |
| 5 | 1994544 |
| 6 | 35901792 |
| 7 | 646232256 |
| 8 | 11632180437 |
| 9 | 209379244788 |
| 10 | 3768826350951 |
| 11 | 67838873322924 |
| 12 | 1221099701917140 |
| 13 | 21979794312389664 |
| 14 | 395636291824874544 |
| 15 | 7121453148481232448 |
[1,19,342,6156,110808,1994544,35901792,646232256, 11632180437,209379244788,3768826350951, 67838873322924,1221099701917140,21979794312389664, 395636291824874544,7121453148481232448] |