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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 112 |
| 5 | 1360 |
| 6 | 19872 |
| 7 | 335104 |
| 8 | 6359040 |
| 9 | 133560576 |
| 10 | 3069007360 |
| 11 | 76493880320 |
| 12 | 2054400577536 |
| 13 | 59136549994496 |
| 14 | 1816392567062528 |
| 15 | 59305340822814720 |
| 16 | 2051451257317490688 |
| 17 | 74958908119819812864 |
| 18 | 2885480280276224311296 |
| 19 | 116731741304854533111808 |
[1,2,12,112,1360,19872,335104,6359040,133560576, 3069007360,76493880320,2054400577536, 59136549994496,1816392567062528,59305340822814720, 2051451257317490688,74958908119819812864, 2885480280276224311296,116731741304854533111808] |