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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 0 |
| 5 | 2 |
| 6 | 4 |
| 7 | 4 |
| 8 | 2 |
| 9 | 6 |
| 10 | 18 |
| 11 | 144 |
| 12 | 15882 |
| 13 | 247684656 |
| 14 | 61339821614663208 |
| 15 | 3762573685332838515711641628032454 |
| 16 | 14156960737559137644661747812427568488753428461913274274176986277422 |
[1,1,1,0,2,4,4,2,6,18,144,15882,247684656, 61339821614663208, 3762573685332838515711641628032454, 14156960737559137644661747812427568488753428461913\ 274274176986277422] |