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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 93 |
| 6 | 345 |
| 7 | 1247 |
| 8 | 4905 |
| 9 | 18621 |
| 10 | 75573 |
| 11 | 297895 |
| 12 | 1235431 |
| 13 | 5004478 |
| 14 | 21069953 |
| 15 | 87081849 |
| 16 | 370961528 |
| 17 | 1556555814 |
| 18 | 6694323743 |
| 19 | 28429384992 |
| 20 | 123233469423 |
| 21 | 528551018694 |
| 22 | 2306190887973 |
| 23 | 9973209794754 |
| 24 | 43756896008712 |
| 25 | 190541968507586 |
| 26 | 839978958124485 |
| 27 | 3679275247472375 |
| 28 | 16287097093699275 |
[1,1,3,8,28,93,345,1247,4905,18621,75573,297895, 1235431,5004478,21069953,87081849,370961528, 1556555814,6694323743,28429384992,123233469423, 528551018694,2306190887973,9973209794754, 43756896008712,190541968507586,839978958124485, 3679275247472375,16287097093699275] |