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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 42 |
| 6 | 282 |
| 7 | 2802 |
| 8 | 42348 |
| 9 | 984576 |
| 10 | 35804724 |
| 11 | 2056887084 |
| 12 | 188218830732 |
| 13 | 27582766315980 |
| 14 | 6497743050809304 |
| 15 | 2466474617607855408 |
| 16 | 1510962789131940581928 |
| 17 | 1495259232837545099449512 |
| 18 | 2391833322688676458284572616 |
| 19 | 6186748984680033744268134049416 |
[0,1,1,3,9,42,282,2802,42348,984576,35804724, 2056887084,188218830732,27582766315980, 6497743050809304,2466474617607855408, 1510962789131940581928,1495259232837545099449512, 2391833322688676458284572616, 6186748984680033744268134049416] |