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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 16 |
| 5 | 174 |
| 6 | 1988 |
| 7 | 27124 |
| 8 | 453136 |
| 9 | 8791980 |
| 10 | 191869392 |
| 11 | 4668291000 |
| 12 | 125662750464 |
| 13 | 3706032771336 |
| 14 | 118759029538368 |
| 15 | 4109063510399088 |
| 16 | 152696171895135744 |
| 17 | 6065376023980289424 |
| 18 | 256455323932682550528 |
| 19 | 11499944141042532006432 |
| 20 | 545124523779848580648960 |
[1,1,2,16,174,1988,27124,453136,8791980,191869392, 4668291000,125662750464,3706032771336, 118759029538368,4109063510399088, 152696171895135744,6065376023980289424, 256455323932682550528,11499944141042532006432, 545124523779848580648960] |