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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 11 |
| 4 | 80 |
| 5 | 714 |
| 6 | 7095 |
| 7 | 76206 |
| 8 | 864590 |
| 9 | 10227727 |
| 10 | 125001862 |
| 11 | 1568419058 |
| 12 | 20108619244 |
| 13 | 262510020319 |
| 14 | 3479914302802 |
| 15 | 46742907726147 |
| 16 | 635092339459857 |
| 17 | 8716058291255777 |
| 18 | 120686879727465365 |
| 19 | 1684357785848110976 |
[1,1,2,11,80,714,7095,76206,864590,10227727, 125001862,1568419058,20108619244,262510020319, 3479914302802,46742907726147,635092339459857, 8716058291255777,120686879727465365, 1684357785848110976] |