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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 26 |
| 4 | 307 |
| 5 | 7764 |
| 6 | 222936 |
| 7 | 3243689 |
| 8 | 132728354 |
| 9 | 30892003921 |
| 10 | 3065366376540 |
| 11 | 74672717363118 |
| 12 | 12952235029243936 |
| 13 | 25923218026065797712 |
| 14 | 11188107558636007931696 |
| 15 | 695394278635888843298780 |
| 16 | 579704015638436450676621584 |
| 17 | 9319830273030294425399538816052 |
[1,4,26,307,7764,222936,3243689,132728354, 30892003921,3065366376540,74672717363118, 12952235029243936,25923218026065797712, 11188107558636007931696,695394278635888843298780, 579704015638436450676621584, 9319830273030294425399538816052] |