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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 37 |
| 4 | 251 |
| 5 | 1947 |
| 6 | 17141 |
| 7 | 167163 |
| 8 | 1779029 |
| 9 | 20456722 |
| 10 | 251997747 |
| 11 | 3303602265 |
| 12 | 45842747207 |
| 13 | 670308495256 |
| 14 | 10288071997990 |
| 15 | 165203260586951 |
| 16 | 2767484369773904 |
| 17 | 48243983405917665 |
| 18 | 873228719542308898 |
| 19 | 16378723735806496553 |
| 20 | 317781161715431909527 |
| 21 | 6367610715649281689454 |
| 22 | 131581260677384045968633 |
[1,2,7,37,251,1947,17141,167163,1779029,20456722, 251997747,3303602265,45842747207,670308495256, 10288071997990,165203260586951,2767484369773904, 48243983405917665,873228719542308898, 16378723735806496553,317781161715431909527, 6367610715649281689454,131581260677384045968633] |