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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 25 |
| 4 | 193 |
| 5 | 1481 |
| 6 | 16021 |
| 7 | 167665 |
| 8 | 2220065 |
| 9 | 30004273 |
| 10 | 468585541 |
| 11 | 7560838121 |
| 12 | 138355144225 |
| 13 | 2589359765305 |
| 14 | 53501800316693 |
| 15 | 1146089983207681 |
| 16 | 26457132132638401 |
| 17 | 632544682981967585 |
| 18 | 16171678558995779845 |
| 19 | 426926324177655018553 |
| 20 | 11938570457328874969601 |
[1,1,5,25,193,1481,16021,167665,2220065,30004273, 468585541,7560838121,138355144225,2589359765305, 53501800316693,1146089983207681,26457132132638401, 632544682981967585,16171678558995779845, 426926324177655018553,11938570457328874969601] |