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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 8 |
| 5 | 50 |
| 6 | 432 |
| 7 | 4802 |
| 8 | 65536 |
| 9 | 1062882 |
| 10 | 20000000 |
| 11 | 428717762 |
| 12 | 10319560704 |
| 13 | 275716983698 |
| 14 | 8099130339328 |
| 15 | 259492675781250 |
| 16 | 9007199254740992 |
| 17 | 336755653118801858 |
| 18 | 13493281232954916864 |
| 19 | 576882827135242335362 |
| 20 | 26214400000000000000000 |
[1,2,8,50,432,4802,65536,1062882,20000000, 428717762,10319560704,275716983698,8099130339328, 259492675781250,9007199254740992, 336755653118801858,13493281232954916864, 576882827135242335362,26214400000000000000000] |