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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 79 |
| 6 | 324 |
| 7 | 1338 |
| 8 | 5370 |
| 9 | 20858 |
| 10 | 79907 |
| 11 | 301917 |
| 12 | 1127753 |
| 13 | 4175945 |
| 14 | 15347222 |
| 15 | 56045572 |
| 16 | 203563012 |
| 17 | 735880196 |
| 18 | 2649245173 |
| 19 | 9502874215 |
| 20 | 33976624115 |
| 21 | 121128306995 |
| 22 | 430701953720 |
| 23 | 1527852568478 |
| 24 | 5408197139806 |
| 25 | 19106052817630 |
| 26 | 67376379676855 |
| 27 | 237205619596129 |
| 28 | 833831061604429 |
| 29 | 2926954896983117 |
[0,1,3,15,79,324,1338,5370,20858,79907,301917, 1127753,4175945,15347222,56045572,203563012, 735880196,2649245173,9502874215,33976624115, 121128306995,430701953720,1527852568478, 5408197139806,19106052817630,67376379676855, 237205619596129,833831061604429,2926954896983117] |