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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 46 |
| 5 | 153 |
| 6 | 677 |
| 7 | 2455 |
| 8 | 11106 |
| 9 | 42895 |
| 10 | 198457 |
| 11 | 791305 |
| 12 | 3702406 |
| 13 | 15165773 |
| 14 | 71734282 |
| 15 | 299266047 |
| 16 | 1425366120 |
| 17 | 6033876043 |
| 18 | 28912348233 |
| 19 | 123853219579 |
| 20 | 596225571156 |
| 21 | 2578099387973 |
| 22 | 12458031648720 |
| 23 | 54309706631855 |
| 24 | 263290014989332 |
| 25 | 1155465606500309 |
| 26 | 5616411745913101 |
| 27 | 24793271401695375 |
[1,1,4,11,46,153,677,2455,11106,42895,198457, 791305,3702406,15165773,71734282,299266047, 1425366120,6033876043,28912348233,123853219579, 596225571156,2578099387973,12458031648720, 54309706631855,263290014989332,1155465606500309, 5616411745913101,24793271401695375] |