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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 27 |
| 5 | 61 |
| 6 | 185 |
| 7 | 469 |
| 8 | 1456 |
| 9 | 4368 |
| 10 | 14720 |
| 11 | 50800 |
| 12 | 190149 |
| 13 | 735451 |
| 14 | 3001161 |
| 15 | 12659652 |
| 16 | 55462967 |
| 17 | 250186665 |
| 18 | 1163114375 |
| 19 | 5548002866 |
| 20 | 27151477487 |
| 21 | 135968479892 |
| 22 | 696511087808 |
| 23 | 3643182769117 |
| 24 | 19449907766921 |
| 25 | 105843172596610 |
[1,4,9,27,61,185,469,1456,4368,14720,50800,190149, 735451,3001161,12659652,55462967,250186665, 1163114375,5548002866,27151477487,135968479892, 696511087808,3643182769117,19449907766921, 105843172596610] |