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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 51 |
| 6 | 189 |
| 7 | 753 |
| 8 | 3248 |
| 9 | 14738 |
| 10 | 70658 |
| 11 | 354178 |
| 12 | 1857703 |
| 13 | 10121033 |
| 14 | 57224955 |
| 15 | 334321008 |
| 16 | 2017234773 |
| 17 | 12530668585 |
| 18 | 80083779383 |
| 19 | 525284893144 |
| 20 | 3533663143981 |
| 21 | 24336720018666 |
| 22 | 171484380988738 |
| 23 | 1234596183001927 |
| 24 | 9075879776056533 |
| 25 | 68052896425955296 |
[1,1,2,5,15,51,189,753,3248,14738,70658,354178, 1857703,10121033,57224955,334321008,2017234773, 12530668585,80083779383,525284893144, 3533663143981,24336720018666,171484380988738, 1234596183001927,9075879776056533, 68052896425955296] |