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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 16 |
| 6 | 61 |
| 7 | 806 |
| 8 | 6329 |
| 9 | 89272 |
| 10 | 1082281 |
| 11 | 17596162 |
| 12 | 284074165 |
| 13 | 5407229972 |
| 14 | 107539072733 |
| 15 | 2380274168806 |
| 16 | 55833426732529 |
| 17 | 1418006883852784 |
| 18 | 38195636967960913 |
| 19 | 1097755724834189834 |
| 20 | 33345176998235584301 |
| 21 | 1071124330593423824908 |
| 22 | 36203857373308709200645 |
[1,0,1,1,16,61,806,6329,89272,1082281,17596162, 284074165,5407229972,107539072733,2380274168806, 55833426732529,1418006883852784,38195636967960913, 1097755724834189834,33345176998235584301, 1071124330593423824908,36203857373308709200645] |