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| n | a(n) |
|---|---|
| 1 | 720 |
| 2 | 3932 |
| 3 | 20816 |
| 4 | 125976 |
| 5 | 716768 |
| 6 | 4674280 |
| 7 | 27765752 |
| 8 | 190316292 |
| 9 | 1159969064 |
| 10 | 8197609072 |
| 11 | 50708447672 |
| 12 | 364761775656 |
| 13 | 2275008360504 |
| 14 | 16527758316992 |
| 15 | 103549619966920 |
| 16 | 756382898620552 |
| 17 | 4750510374920744 |
| 18 | 34803101628502320 |
[720,3932,20816,125976,716768,4674280,27765752, 190316292,1159969064,8197609072,50708447672, 364761775656,2275008360504,16527758316992, 103549619966920,756382898620552,4750510374920744, 34803101628502320] |