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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 39 |
| 4 | 269 |
| 5 | 1917 |
| 6 | 13893 |
| 7 | 101830 |
| 8 | 753255 |
| 9 | 5614504 |
| 10 | 42110432 |
| 11 | 317474187 |
| 12 | 2403893757 |
| 13 | 18270065438 |
| 14 | 139305459960 |
| 15 | 1065183756535 |
| 16 | 8165168139498 |
| 17 | 62729216570805 |
| 18 | 482878316552298 |
| 19 | 3723769699813119 |
| 20 | 28762830132956421 |
| 21 | 222495155932381229 |
| 22 | 1723432870654770161 |
| 23 | 13366099075223254740 |
[1,6,39,269,1917,13893,101830,753255,5614504, 42110432,317474187,2403893757,18270065438, 139305459960,1065183756535,8165168139498, 62729216570805,482878316552298,3723769699813119, 28762830132956421,222495155932381229, 1723432870654770161,13366099075223254740] |