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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 70 |
| 5 | 7 |
| 6 | 77 |
| 7 | 1001 |
| 8 | 20020 |
| 9 | 255255 |
| 10 | 1616615 |
| 11 | 1616615 |
| 12 | 74364290 |
| 13 | 185910725 |
| 14 | 79676025 |
| 15 | 770201575 |
| 16 | 191009990600 |
| 17 | 2170568075 |
| 18 | 45581929575 |
| 19 | 562177131425 |
| 20 | 1124354262850 |
| 21 | 3292751769775 |
| 22 | 1557471587103575 |
| 23 | 1557471587103575 |
[1,1,5,70,7,77,1001,20020,255255,1616615,1616615, 74364290,185910725,79676025,770201575, 191009990600,2170568075,45581929575,562177131425, 1124354262850,3292751769775,1557471587103575, 1557471587103575] |