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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 17 |
| 5 | 36 |
| 6 | 369 |
| 7 | 1820 |
| 8 | 20808 |
| 9 | 47280 |
| 10 | 246561 |
| 11 | 6919153 |
| 12 | 16008300 |
| 13 | 1086517900 |
| 14 | 5924129729 |
| 15 | 13855173264 |
| 16 | 982740019940 |
| 17 | 30127233316440 |
| 18 | 167427203210673 |
| 19 | 5203545562472737 |
| 20 | 12300752138736600 |
| 21 | 913640750713307860 |
| 22 | 162500024938034177361 |
[1,2,4,17,36,369,1820,20808,47280,246561,6919153, 16008300,1086517900,5924129729,13855173264, 982740019940,30127233316440,167427203210673, 5203545562472737,12300752138736600, 913640750713307860,162500024938034177361] |