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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 35 |
| 4 | 216 |
| 5 | 1527 |
| 6 | 11927 |
| 7 | 101056 |
| 8 | 920055 |
| 9 | 8960343 |
| 10 | 93202418 |
| 11 | 1035640333 |
| 12 | 12305625141 |
| 13 | 156513872514 |
| 14 | 2131781868823 |
| 15 | 31077520424879 |
| 16 | 484157377851360 |
| 17 | 8040920113043655 |
| 18 | 141937291242762263 |
| 19 | 2654252437895865112 |
| 20 | 52412046969340405371 |
| 21 | 1089506079309378596823 |
[1,2,7,35,216,1527,11927,101056,920055,8960343, 93202418,1035640333,12305625141,156513872514, 2131781868823,31077520424879,484157377851360, 8040920113043655,141937291242762263, 2654252437895865112,52412046969340405371, 1089506079309378596823] |