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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 11 |
| 6 | 32 |
| 7 | 99 |
| 8 | 326 |
| 9 | 1123 |
| 10 | 4064 |
| 11 | 15291 |
| 12 | 59924 |
| 13 | 242945 |
| 14 | 1019584 |
| 15 | 4409233 |
| 16 | 19648674 |
| 17 | 89938705 |
| 18 | 422744384 |
| 19 | 2035739041 |
| 20 | 10039057524 |
| 21 | 50610247483 |
| 22 | 260704414816 |
| 23 | 1370387233859 |
| 24 | 7346982653702 |
| 25 | 40131663286851 |
| 26 | 223238920709024 |
| 27 | 1263531826402891 |
| 28 | 7273434344119460 |
[1,1,1,1,4,11,32,99,326,1123,4064,15291,59924, 242945,1019584,4409233,19648674,89938705, 422744384,2035739041,10039057524,50610247483, 260704414816,1370387233859,7346982653702, 40131663286851,223238920709024,1263531826402891, 7273434344119460] |