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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 2 |
| 3 | 6 |
| 4 | 10 |
| 5 | 38 |
| 6 | 84 |
| 7 | 462 |
| 8 | 1454 |
| 9 | 10978 |
| 10 | 47966 |
| 11 | 507832 |
| 12 | 3102956 |
| 13 | 45765610 |
| 14 | 389928206 |
| 15 | 8030198134 |
| 16 | 95507073248 |
| 17 | 2744133148026 |
| 18 | 45539464036516 |
| 19 | 1826082647001502 |
| 20 | 42290971759195390 |
| 21 | 2366417546297792380 |
| 22 | 76478152220819322380 |
[1,2,2,6,10,38,84,462,1454,10978,47966,507832, 3102956,45765610,389928206,8030198134,95507073248, 2744133148026,45539464036516,1826082647001502, 42290971759195390,2366417546297792380, 76478152220819322380] |