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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 36 |
| 5 | 236 |
| 6 | 1824 |
| 7 | 15920 |
| 8 | 152902 |
| 9 | 1589049 |
| 10 | 17664790 |
| 11 | 208322454 |
| 12 | 2590298272 |
| 13 | 33798788538 |
| 14 | 461078981884 |
| 15 | 6556432452540 |
| 16 | 96939246851454 |
| 17 | 1487173494072195 |
| 18 | 23630403273226874 |
| 19 | 388278726368516603 |
| 20 | 6588263758154705850 |
[1,2,7,36,236,1824,15920,152902,1589049,17664790, 208322454,2590298272,33798788538,461078981884, 6556432452540,96939246851454,1487173494072195, 23630403273226874,388278726368516603, 6588263758154705850] |