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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 40 |
| 5 | 351 |
| 6 | 4876 |
| 7 | 104748 |
| 8 | 3487153 |
| 9 | 179921982 |
| 10 | 14387581923 |
| 11 | 1783124902639 |
| 12 | 342504341570010 |
| 13 | 101962565961894431 |
| 14 | 47044167891731682278 |
| 15 | 33640402686770010577421 |
| 16 | 37282664267078280296013183 |
| 17 | 64038780633654058635677191329 |
| 18 | 170478465430659361252118580217675 |
[1,1,2,7,40,351,4876,104748,3487153,179921982, 14387581923,1783124902639,342504341570010, 101962565961894431,47044167891731682278, 33640402686770010577421, 37282664267078280296013183, 64038780633654058635677191329, 170478465430659361252118580217675] |