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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 19 |
| 2 | 178 |
| 3 | 1656 |
| 4 | 15352 |
| 5 | 142064 |
| 6 | 1313408 |
| 7 | 12136896 |
| 8 | 112126592 |
| 9 | 1035748864 |
| 10 | 9566914048 |
| 11 | 88363846656 |
| 12 | 816149635072 |
| 13 | 7538085638144 |
| 14 | 69622614990848 |
| 15 | 643040841793536 |
| 16 | 5939176725512192 |
| 17 | 54854677118255104 |
| 18 | 506641703733035008 |
[2,19,178,1656,15352,142064,1313408,12136896, 112126592,1035748864,9566914048,88363846656, 816149635072,7538085638144,69622614990848, 643040841793536,5939176725512192, 54854677118255104,506641703733035008] |