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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 11 |
| 2 | 40 |
| 3 | 149 |
| 4 | 556 |
| 5 | 2075 |
| 6 | 7744 |
| 7 | 28901 |
| 8 | 107860 |
| 9 | 402539 |
| 10 | 1502296 |
| 11 | 5606645 |
| 12 | 20924284 |
| 13 | 78090491 |
| 14 | 291437680 |
| 15 | 1087660229 |
| 16 | 4059203236 |
| 17 | 15149152715 |
| 18 | 56537407624 |
| 19 | 211000477781 |
| 20 | 787464503500 |
| 21 | 2938857536219 |
| 22 | 10967965641376 |
[4,11,40,149,556,2075,7744,28901,107860,402539, 1502296,5606645,20924284,78090491,291437680, 1087660229,4059203236,15149152715,56537407624, 211000477781,787464503500,2938857536219, 10967965641376] |