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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 9 |
| 3 | 22 |
| 4 | 57 |
| 5 | 146 |
| 6 | 367 |
| 7 | 946 |
| 8 | 2507 |
| 9 | 6634 |
| 10 | 17777 |
| 11 | 48522 |
| 12 | 133107 |
| 13 | 369020 |
| 14 | 1028405 |
| 15 | 2880288 |
| 16 | 8100949 |
| 17 | 22877146 |
| 18 | 64823569 |
| 19 | 184274932 |
| 20 | 525282741 |
| 21 | 1501215194 |
| 22 | 4299836187 |
| 23 | 12340952050 |
| 24 | 35486796313 |
| 25 | 102220582466 |
| 26 | 294917666855 |
| 27 | 852123981582 |
| 28 | 2465458792769 |
[4,9,22,57,146,367,946,2507,6634,17777,48522, 133107,369020,1028405,2880288,8100949,22877146, 64823569,184274932,525282741,1501215194, 4299836187,12340952050,35486796313,102220582466, 294917666855,852123981582,2465458792769] |