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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 12 |
| 4 | 88 |
| 5 | 625 |
| 6 | 5648 |
| 7 | 52208 |
| 8 | 505857 |
| 9 | 4992048 |
| 10 | 50169067 |
| 11 | 510807173 |
| 12 | 5260218485 |
| 13 | 54684221779 |
| 14 | 573168585795 |
| 15 | 6050541798221 |
| 16 | 64271927631233 |
| 17 | 686512535921878 |
| 18 | 7369066749454264 |
| 19 | 79449368494683376 |
| 20 | 859987831858141180 |
| 21 | 9342319735394175920 |
| 22 | 101820772577694786504 |
[1,4,12,88,625,5648,52208,505857,4992048,50169067, 510807173,5260218485,54684221779,573168585795, 6050541798221,64271927631233,686512535921878, 7369066749454264,79449368494683376, 859987831858141180,9342319735394175920, 101820772577694786504] |