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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 36 |
| 4 | 465 |
| 5 | 1323 |
| 6 | 9045 |
| 7 | 38646 |
| 8 | 117582 |
| 9 | 334656 |
| 10 | 1429893 |
| 11 | 4350525 |
| 12 | 18588606 |
| 13 | 87223458 |
| 14 | 265382010 |
| 15 | 928000395 |
| 16 | 4702917255 |
| 17 | 5989820730 |
| 18 | 12064005132 |
| 19 | 56608024080 |
[1,3,36,465,1323,9045,38646,117582,334656,1429893, 4350525,18588606,87223458,265382010,928000395, 4702917255,5989820730,12064005132,56608024080] |