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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 21 |
| 3 | 162 |
| 4 | 1365 |
| 5 | 12219 |
| 6 | 114156 |
| 7 | 1100649 |
| 8 | 10871175 |
| 9 | 109438830 |
| 10 | 1118798079 |
| 11 | 11583712617 |
| 12 | 121219182504 |
| 13 | 1280065637487 |
| 14 | 13623341795049 |
| 15 | 145977237305874 |
| 16 | 1573536198376401 |
| 17 | 17051418418204671 |
| 18 | 185646639499541892 |
[1,3,21,162,1365,12219,114156,1100649,10871175, 109438830,1118798079,11583712617,121219182504, 1280065637487,13623341795049,145977237305874, 1573536198376401,17051418418204671, 185646639499541892] |