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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 63 |
| 4 | 423 |
| 5 | 3528 |
| 6 | 35559 |
| 7 | 422901 |
| 8 | 5817744 |
| 9 | 91072269 |
| 10 | 1600588269 |
| 11 | 31230827532 |
| 12 | 670252672593 |
| 13 | 15696888917427 |
| 14 | 398454496989012 |
| 15 | 10899543418960167 |
| 16 | 319672849622745951 |
| 17 | 10007954229075765984 |
| 18 | 333139545206104991031 |
| 19 | 11749955670275356579941 |
[1,3,12,63,423,3528,35559,422901,5817744,91072269, 1600588269,31230827532,670252672593, 15696888917427,398454496989012,10899543418960167, 319672849622745951,10007954229075765984, 333139545206104991031,11749955670275356579941] |