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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 43 |
| 5 | 252 |
| 6 | 1636 |
| 7 | 11322 |
| 8 | 81805 |
| 9 | 610358 |
| 10 | 4672836 |
| 11 | 36525052 |
| 12 | 290399543 |
| 13 | 2342043630 |
| 14 | 19118822650 |
| 15 | 157709971144 |
| 16 | 1312796873451 |
| 17 | 11015236989702 |
| 18 | 93078467831012 |
| 19 | 791462018168032 |
| 20 | 6767910089071288 |
| 21 | 58167781282121262 |
[1,2,8,43,252,1636,11322,81805,610358,4672836, 36525052,290399543,2342043630,19118822650, 157709971144,1312796873451,11015236989702, 93078467831012,791462018168032,6767910089071288, 58167781282121262] |