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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 7 |
| 4 | 14 |
| 5 | 31 |
| 6 | 84 |
| 7 | 195 |
| 8 | 482 |
| 9 | 1131 |
| 10 | 2620 |
| 11 | 5957 |
| 12 | 13502 |
| 13 | 29911 |
| 14 | 65820 |
| 15 | 143551 |
| 16 | 311074 |
| 17 | 669543 |
| 18 | 1435388 |
| 19 | 3061571 |
| 20 | 6503526 |
| 21 | 13771989 |
| 22 | 29061728 |
| 23 | 61159219 |
| 24 | 128372210 |
| 25 | 268845359 |
| 26 | 561835492 |
| 27 | 1171862289 |
| 28 | 2440014306 |
| 29 | 5072185867 |
| 30 | 10528184756 |
[2,4,7,14,31,84,195,482,1131,2620,5957,13502, 29911,65820,143551,311074,669543,1435388,3061571, 6503526,13771989,29061728,61159219,128372210, 268845359,561835492,1171862289,2440014306, 5072185867,10528184756] |