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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 36757 |
| 9 | 223898 |
| 10 | 1055479 |
| 11 | 3973264 |
| 12 | 12530496 |
| 13 | 34434065 |
| 14 | 84883448 |
| 15 | 191729212 |
| 16 | 403095882 |
| 17 | 798248632 |
| 18 | 1502630530 |
| 19 | 2708156958 |
| 20 | 4700026333 |
| 21 | 7891491375 |
| 22 | 12868232903 |
| 23 | 20444188490 |
| 24 | 31730911273 |
| 25 | 48222769794 |
| 26 | 71900547943 |
[1,2,6,24,120,720,5040,36757,223898,1055479, 3973264,12530496,34434065,84883448,191729212, 403095882,798248632,1502630530,2708156958, 4700026333,7891491375,12868232903,20444188490, 31730911273,48222769794,71900547943] |