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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 32 |
| 4 | 225 |
| 5 | 1652 |
| 6 | 12404 |
| 7 | 94320 |
| 8 | 722733 |
| 9 | 5565560 |
| 10 | 43005391 |
| 11 | 333132384 |
| 12 | 2585476348 |
| 13 | 20097106512 |
| 14 | 156418938680 |
| 15 | 1218807197408 |
| 16 | 9506457334965 |
| 17 | 74216779041840 |
| 18 | 579903491112365 |
| 19 | 4534776883051800 |
| 20 | 35488119754971345 |
[1,5,32,225,1652,12404,94320,722733,5565560, 43005391,333132384,2585476348,20097106512, 156418938680,1218807197408,9506457334965, 74216779041840,579903491112365,4534776883051800, 35488119754971345] |