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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 10 |
| 4 | 55 |
| 5 | 307 |
| 6 | 2026 |
| 7 | 14779 |
| 8 | 114157 |
| 9 | 933616 |
| 10 | 8110261 |
| 11 | 74525167 |
| 12 | 719925328 |
| 13 | 7279859485 |
| 14 | 76855303981 |
| 15 | 845280487018 |
| 16 | 9663800287483 |
| 17 | 114601481983855 |
| 18 | 1407040763488354 |
| 19 | 17856103120048783 |
| 20 | 233883061849700137 |
| 21 | 3157648445216335528 |
| 22 | 43887908697233605489 |
[0,1,1,10,55,307,2026,14779,114157,933616,8110261, 74525167,719925328,7279859485,76855303981, 845280487018,9663800287483,114601481983855, 1407040763488354,17856103120048783, 233883061849700137,3157648445216335528, 43887908697233605489] |