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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 11 |
| 6 | 61 |
| 7 | 507 |
| 8 | 7442 |
| 9 | 197772 |
| 10 | 9808209 |
| 11 | 902884343 |
| 12 | 153723152913 |
| 13 | 48443147912137 |
| 14 | 28363697921914475 |
| 15 | 30996525982586676021 |
| 16 | 63502034385272108655525 |
| 17 | 244852545421597419740767106 |
| 18 | 1783161611489937453151313949442 |
| 19 | 24603891216883233547700609793901996 |
[1,1,0,1,3,11,61,507,7442,197772,9808209, 902884343,153723152913,48443147912137, 28363697921914475,30996525982586676021, 63502034385272108655525, 244852545421597419740767106, 1783161611489937453151313949442, 24603891216883233547700609793901996] |