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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 15 |
| 5 | 33 |
| 6 | 75 |
| 7 | 169 |
| 8 | 375 |
| 9 | 835 |
| 10 | 1875 |
| 11 | 4203 |
| 12 | 9375 |
| 13 | 20931 |
| 14 | 46875 |
| 15 | 104919 |
| 16 | 234375 |
| 17 | 523737 |
| 18 | 1171875 |
| 19 | 2621545 |
| 20 | 5859375 |
| 21 | 13098001 |
| 22 | 29296875 |
| 23 | 65523597 |
| 24 | 146484375 |
| 25 | 327500413 |
| 26 | 732421875 |
| 27 | 1637918089 |
[1,1,3,7,15,33,75,169,375,835,1875,4203,9375, 20931,46875,104919,234375,523737,1171875,2621545, 5859375,13098001,29296875,65523597,146484375, 327500413,732421875,1637918089] |