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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 37 |
| 5 | 187 |
| 6 | 1304 |
| 7 | 14606 |
| 8 | 222379 |
| 9 | 4141729 |
| 10 | 107836478 |
| 11 | 4466744372 |
| 12 | 258501941713 |
| 13 | 18779494904263 |
| 14 | 1918824942497636 |
| 15 | 311738238353418074 |
| 16 | 71234670515346760951 |
| 17 | 20564497734374127115501 |
| 18 | 8363824677163863282113162 |
| 19 | 5408580882753786431279731328 |
[1,1,2,8,37,187,1304,14606,222379,4141729, 107836478,4466744372,258501941713,18779494904263, 1918824942497636,311738238353418074, 71234670515346760951,20564497734374127115501, 8363824677163863282113162, 5408580882753786431279731328] |