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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 40 |
| 4 | 447 |
| 5 | 6421 |
| 6 | 112726 |
| 7 | 2338799 |
| 8 | 55990213 |
| 9 | 1519122598 |
| 10 | 46066158817 |
| 11 | 1543974969769 |
| 12 | 56677405835276 |
| 13 | 2261488166321697 |
| 14 | 97455090037460785 |
| 15 | 4510770674565054000 |
| 16 | 223183550978156866507 |
| 17 | 11755122645815049275521 |
| 18 | 656670295411196201190366 |
| 19 | 38779502115371642484125915 |
| 20 | 2413908564514961126280655257 |
[1,1,5,40,447,6421,112726,2338799,55990213, 1519122598,46066158817,1543974969769, 56677405835276,2261488166321697,97455090037460785, 4510770674565054000,223183550978156866507, 11755122645815049275521,656670295411196201190366, 38779502115371642484125915, 2413908564514961126280655257] |