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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 11 |
| 3 | 27 |
| 4 | 66 |
| 5 | 161 |
| 6 | 389 |
| 7 | 940 |
| 8 | 2271 |
| 9 | 5483 |
| 10 | 13238 |
| 11 | 31961 |
| 12 | 77161 |
| 13 | 186284 |
| 14 | 449731 |
| 15 | 1085747 |
| 16 | 2621226 |
| 17 | 6328201 |
| 18 | 15277629 |
| 19 | 36883460 |
| 20 | 89044551 |
| 21 | 214972563 |
| 22 | 518989678 |
| 23 | 1252951921 |
| 24 | 3024893521 |
| 25 | 7302738964 |
| 26 | 17630371451 |
| 27 | 42563481867 |
| 28 | 102757335186 |
[1,4,11,27,66,161,389,940,2271,5483,13238,31961, 77161,186284,449731,1085747,2621226,6328201, 15277629,36883460,89044551,214972563,518989678, 1252951921,3024893521,7302738964,17630371451, 42563481867,102757335186] |