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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 34 |
| 6 | 117 |
| 7 | 380 |
| 8 | 1406 |
| 9 | 4999 |
| 10 | 19436 |
| 11 | 73281 |
| 12 | 294911 |
| 13 | 1158933 |
| 14 | 4783572 |
| 15 | 19380630 |
| 16 | 81559299 |
| 17 | 338222235 |
| 18 | 1445214303 |
| 19 | 6103689409 |
| 20 | 26403873389 |
| 21 | 113158587598 |
| 22 | 494494330837 |
| 23 | 2144745995381 |
| 24 | 9452119592037 |
| 25 | 41405093641107 |
| 26 | 183792698163773 |
| 27 | 811852822076853 |
| 28 | 3626027169072513 |
[1,1,2,4,12,34,117,380,1406,4999,19436,73281, 294911,1158933,4783572,19380630,81559299, 338222235,1445214303,6103689409,26403873389, 113158587598,494494330837,2144745995381, 9452119592037,41405093641107,183792698163773, 811852822076853,3626027169072513] |