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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 9 |
| 3 | 73 |
| 4 | 621 |
| 5 | 5229 |
| 6 | 44293 |
| 7 | 374277 |
| 8 | 3162447 |
| 9 | 26694159 |
| 10 | 225163687 |
| 11 | 1897751079 |
| 12 | 15983278059 |
| 13 | 134519816427 |
| 14 | 1131395821587 |
| 15 | 9509592524371 |
| 16 | 79880259426102 |
| 17 | 670590654977718 |
| 18 | 5626336598011078 |
| 19 | 47179486350900358 |
| 20 | 395410837699366686 |
| 21 | 3312225325409475038 |
| 22 | 27731588831310844302 |
[1,1,9,73,621,5229,44293,374277,3162447,26694159, 225163687,1897751079,15983278059,134519816427, 1131395821587,9509592524371,79880259426102, 670590654977718,5626336598011078, 47179486350900358,395410837699366686, 3312225325409475038,27731588831310844302] |