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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 31 |
| 3 | 217 |
| 4 | 1806 |
| 5 | 13422 |
| 6 | 91755 |
| 7 | 633413 |
| 8 | 4472626 |
| 9 | 30905995 |
| 10 | 209517906 |
| 11 | 1388328518 |
| 12 | 9240921228 |
| 13 | 61120602235 |
| 14 | 401793563633 |
| 15 | 2619241322237 |
| 16 | 17009669381881 |
| 17 | 110033650331158 |
| 18 | 709134941588286 |
[6,31,217,1806,13422,91755,633413,4472626, 30905995,209517906,1388328518,9240921228, 61120602235,401793563633,2619241322237, 17009669381881,110033650331158,709134941588286] |