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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 88 |
| 4 | 1164 |
| 5 | 21228 |
| 6 | 505108 |
| 7 | 15088400 |
| 8 | 549924048 |
| 9 | 23922798360 |
| 10 | 1220592387496 |
| 11 | 72008007861128 |
| 12 | 4853864641010384 |
| 13 | 370112914857814360 |
| 14 | 31651011896528812776 |
| 15 | 3013092750843813488640 |
| 16 | 317232128940068230592960 |
| 17 | 36726669357239166496674080 |
[1,2,10,88,1164,21228,505108,15088400,549924048, 23922798360,1220592387496,72008007861128, 4853864641010384,370112914857814360, 31651011896528812776,3013092750843813488640, 317232128940068230592960, 36726669357239166496674080] |