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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 66 |
| 4 | 483 |
| 5 | 4476 |
| 6 | 50454 |
| 7 | 671649 |
| 8 | 10328118 |
| 9 | 180341094 |
| 10 | 3527385345 |
| 11 | 76435691250 |
| 12 | 1818255212490 |
| 13 | 47118807865863 |
| 14 | 1321527658352016 |
| 15 | 39889359465259446 |
| 16 | 1289471521115731611 |
| 17 | 44450463108654209136 |
| 18 | 1627806562174453037802 |
[1,3,12,66,483,4476,50454,671649,10328118, 180341094,3527385345,76435691250,1818255212490, 47118807865863,1321527658352016,39889359465259446, 1289471521115731611,44450463108654209136, 1627806562174453037802] |