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| n | a(n) |
|---|---|
| 6 | 1 |
| 7 | 63 |
| 8 | 2842 |
| 9 | 116172 |
| 10 | 4654713 |
| 11 | 189142107 |
| 12 | 7923937307 |
| 13 | 345104368752 |
| 14 | 15688849238062 |
| 15 | 745831503236820 |
| 16 | 37094603885430728 |
| 17 | 1929672890969261256 |
| 18 | 104918114960824458448 |
| 19 | 5956513043619244790970 |
| 20 | 352719666690509340493680 |
| 21 | 21759830035878816514854144 |
[1,63,2842,116172,4654713,189142107,7923937307, 345104368752,15688849238062,745831503236820, 37094603885430728,1929672890969261256, 104918114960824458448,5956513043619244790970, 352719666690509340493680, 21759830035878816514854144] |