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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 39 |
| 5 | 387 |
| 6 | 4960 |
| 7 | 74088 |
| 8 | 1312716 |
| 9 | 26239484 |
| 10 | 595023510 |
| 11 | 14908285892 |
| 12 | 412903136867 |
| 13 | 12448252189622 |
| 14 | 407804188400373 |
| 15 | 14380454869464352 |
| 16 | 544428684832123828 |
| 17 | 21991444994187529639 |
| 18 | 945234507638271696504 |
| 19 | 43042162953650721470752 |
| 20 | 2071216980365429970912347 |
[1,1,5,39,387,4960,74088,1312716,26239484, 595023510,14908285892,412903136867,12448252189622, 407804188400373,14380454869464352, 544428684832123828,21991444994187529639, 945234507638271696504,43042162953650721470752, 2071216980365429970912347] |