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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 61 |
| 5 | 310 |
| 6 | 1657 |
| 7 | 9190 |
| 8 | 52393 |
| 9 | 305155 |
| 10 | 1807922 |
| 11 | 10861507 |
| 12 | 66013637 |
| 13 | 405162518 |
| 14 | 2507635730 |
| 15 | 15633283370 |
| 16 | 98082119253 |
| 17 | 618809792699 |
| 18 | 3923563925805 |
| 19 | 24988037929779 |
| 20 | 159778209864528 |
| 21 | 1025347017029433 |
| 22 | 6601594402837783 |
| 23 | 42631140337468305 |
[1,1,3,13,61,310,1657,9190,52393,305155,1807922, 10861507,66013637,405162518,2507635730, 15633283370,98082119253,618809792699, 3923563925805,24988037929779,159778209864528, 1025347017029433,6601594402837783, 42631140337468305] |