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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 36 |
| 3 | 524 |
| 4 | 10756 |
| 5 | 288764 |
| 6 | 9667476 |
| 7 | 390576684 |
| 8 | 18591797156 |
| 9 | 1023871865244 |
| 10 | 64308208060916 |
| 11 | 4553899456432844 |
| 12 | 360155907603064196 |
| 13 | 31561618500966519484 |
| 14 | 3044291843751868832596 |
| 15 | 321353247687162678690924 |
[1,4,36,524,10756,288764,9667476,390576684, 18591797156,1023871865244,64308208060916, 4553899456432844,360155907603064196, 31561618500966519484,3044291843751868832596, 321353247687162678690924] |