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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 63 |
| 4 | 454 |
| 5 | 3539 |
| 6 | 29008 |
| 7 | 246255 |
| 8 | 2145722 |
| 9 | 19078536 |
| 10 | 172402396 |
| 11 | 1578687082 |
| 12 | 14616730080 |
| 13 | 136606848093 |
| 14 | 1287022395324 |
| 15 | 12210382758519 |
| 16 | 116553763025178 |
| 17 | 1118580919711060 |
| 18 | 10786838228669692 |
| 19 | 104469304517331666 |
| 20 | 1015700422725526916 |
[1,2,10,63,454,3539,29008,246255,2145722,19078536, 172402396,1578687082,14616730080,136606848093, 1287022395324,12210382758519,116553763025178, 1118580919711060,10786838228669692, 104469304517331666,1015700422725526916] |