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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 20 |
| 4 | 364 |
| 5 | 17017 |
| 6 | 2097018 |
| 7 | 674740506 |
| 8 | 568965009030 |
| 9 | 1255571292290712 |
| 10 | 7254987185250544104 |
| 11 | 109744478168199574282739 |
| 12 | 4346236474244131564253156182 |
| 13 | 450625464087974723307205504432150 |
| 14 | 122319234225590858340579679211039433810 |
[1,1,3,20,364,17017,2097018,674740506, 568965009030,1255571292290712,7254987185250544104, 109744478168199574282739, 4346236474244131564253156182, 450625464087974723307205504432150, 122319234225590858340579679211039433810] |