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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 43 |
| 4 | 1252 |
| 5 | 104098 |
| 6 | 25511272 |
| 7 | 18649337311 |
| 8 | 40823535032644 |
| 9 | 267924955577741566 |
| 10 | 5274102955963545775864 |
| 11 | 311441054994969341088610030 |
| 12 | 55171471477692117486494217498280 |
[1,1,4,43,1252,104098,25511272,18649337311, 40823535032644,267924955577741566, 5274102955963545775864, 311441054994969341088610030, 55171471477692117486494217498280] |