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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 11 |
| 2 | 50 |
| 3 | 348 |
| 4 | 2712 |
| 5 | 23520 |
| 6 | 225360 |
| 7 | 2368800 |
| 8 | 27135360 |
| 9 | 336752640 |
| 10 | 4503340800 |
| 11 | 64585382400 |
| 12 | 989138304000 |
| 13 | 16115529830400 |
| 14 | 278360283801600 |
| 15 | 5081622594048000 |
| 16 | 97772197146624000 |
| 17 | 1977622100213760000 |
[2,11,50,348,2712,23520,225360,2368800,27135360, 336752640,4503340800,64585382400,989138304000, 16115529830400,278360283801600,5081622594048000, 97772197146624000,1977622100213760000] |