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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 13 |
| 3 | 63 |
| 4 | 283 |
| 5 | 1492 |
| 6 | 8019 |
| 7 | 45270 |
| 8 | 261219 |
| 9 | 1542254 |
| 10 | 9251023 |
| 11 | 56269627 |
| 12 | 346115245 |
| 13 | 2149556612 |
| 14 | 13459568885 |
| 15 | 84879754663 |
| 16 | 538612428155 |
| 17 | 3436623582022 |
| 18 | 22034604531623 |
| 19 | 141897138868677 |
| 20 | 917376314956897 |
[1,6,13,63,283,1492,8019,45270,261219,1542254, 9251023,56269627,346115245,2149556612,13459568885, 84879754663,538612428155,3436623582022, 22034604531623,141897138868677,917376314956897] |