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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 23 |
| 7 | 65 |
| 8 | 199 |
| 9 | 654 |
| 10 | 2296 |
| 11 | 8569 |
| 12 | 33825 |
| 13 | 140580 |
| 14 | 612890 |
| 15 | 2794159 |
| 16 | 13280627 |
| 17 | 65597882 |
| 18 | 335521900 |
| 19 | 1770176005 |
| 20 | 9593485125 |
| 21 | 53183385680 |
| 22 | 300371056446 |
| 23 | 1721926382427 |
| 24 | 9987133305239 |
| 25 | 58446578859494 |
| 26 | 344361988828048 |
[1,1,2,4,9,23,65,199,654,2296,8569,33825,140580, 612890,2794159,13280627,65597882,335521900, 1770176005,9593485125,53183385680,300371056446, 1721926382427,9987133305239,58446578859494, 344361988828048] |