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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 50 |
| 6 | 182 |
| 7 | 707 |
| 8 | 2903 |
| 9 | 12479 |
| 10 | 55844 |
| 11 | 258860 |
| 12 | 1238588 |
| 13 | 6099054 |
| 14 | 30836886 |
| 15 | 159770751 |
| 16 | 846927495 |
| 17 | 4586883023 |
| 18 | 25351486346 |
| 19 | 142843162421 |
| 20 | 819783142271 |
| 21 | 4788268962584 |
| 22 | 28444114318056 |
| 23 | 171737405798836 |
| 24 | 1053285775758916 |
| 25 | 6558551535958516 |
| 26 | 41441942236323008 |
[1,1,2,5,15,50,182,707,2903,12479,55844,258860, 1238588,6099054,30836886,159770751,846927495, 4586883023,25351486346,142843162421,819783142271, 4788268962584,28444114318056,171737405798836, 1053285775758916,6558551535958516, 41441942236323008] |