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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 54 |
| 6 | 232 |
| 7 | 1194 |
| 8 | 5348 |
| 9 | 28874 |
| 10 | 153508 |
| 11 | 860486 |
| 12 | 4887496 |
| 13 | 36291722 |
| 14 | 265127656 |
| 15 | 2037271658 |
| 16 | 15840444682 |
[1,2,6,16,54,232,1194,5348,28874,153508,860486, 4887496,36291722,265127656,2037271658,15840444682] |