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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 45 |
| 3 | 680 |
| 4 | 20475 |
| 5 | 1533939 |
| 6 | 350161812 |
| 7 | 280384608504 |
| 8 | 847073824772175 |
| 9 | 9894081531608130857 |
| 10 | 446730013630787463700695 |
| 11 | 77328499046923986969058944720 |
| 12 | 50891283683781760304442885961988100 |
[1,5,45,680,20475,1533939,350161812,280384608504, 847073824772175,9894081531608130857, 446730013630787463700695, 77328499046923986969058944720, 50891283683781760304442885961988100] |