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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 14 |
| 3 | 156 |
| 4 | 2404 |
| 5 | 47310 |
| 6 | 1133362 |
| 7 | 32005400 |
| 8 | 1041071208 |
| 9 | 38332962810 |
| 10 | 1576117028870 |
| 11 | 71578863309492 |
| 12 | 3558526264337420 |
| 13 | 192218569184875142 |
| 14 | 11210020924481677690 |
| 15 | 702004358782658232240 |
| 16 | 46983434611147824097104 |
| 17 | 3346765071252016227670386 |
| 18 | 252810562072190606804106894 |
[1,2,14,156,2404,47310,1133362,32005400, 1041071208,38332962810,1576117028870, 71578863309492,3558526264337420, 192218569184875142,11210020924481677690, 702004358782658232240,46983434611147824097104, 3346765071252016227670386, 252810562072190606804106894] |