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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 45 |
| 5 | 195 |
| 6 | 885 |
| 7 | 4153 |
| 8 | 19983 |
| 9 | 98055 |
| 10 | 488805 |
| 11 | 2468545 |
| 12 | 12602743 |
| 13 | 64937493 |
| 14 | 337264163 |
| 15 | 1763752075 |
| 16 | 9279601413 |
| 17 | 49084160037 |
| 18 | 260867197263 |
| 19 | 1392352081031 |
| 20 | 7460146494529 |
| 21 | 40110432099247 |
| 22 | 216343171411657 |
[1,1,3,11,45,195,885,4153,19983,98055,488805, 2468545,12602743,64937493,337264163,1763752075, 9279601413,49084160037,260867197263,1392352081031, 7460146494529,40110432099247,216343171411657] |