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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 73 |
| 4 | 528 |
| 5 | 4017 |
| 6 | 31607 |
| 7 | 254779 |
| 8 | 2091647 |
| 9 | 17420270 |
| 10 | 146780121 |
| 11 | 1248679940 |
| 12 | 10708942769 |
| 13 | 92478844907 |
| 14 | 803403848506 |
| 15 | 7016088024023 |
| 16 | 61554363004544 |
| 17 | 542255447285265 |
| 18 | 4794512298020555 |
| 19 | 42532684423049866 |
| 20 | 378446187960196753 |
| 21 | 3376541608977259909 |
[1,2,11,73,528,4017,31607,254779,2091647,17420270, 146780121,1248679940,10708942769,92478844907, 803403848506,7016088024023,61554363004544, 542255447285265,4794512298020555, 42532684423049866,378446187960196753, 3376541608977259909] |