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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 15 |
| 2 | 240 |
| 3 | 3840 |
| 4 | 61440 |
| 5 | 983040 |
| 6 | 15728640 |
| 7 | 251658240 |
| 8 | 4026531840 |
| 9 | 64424509440 |
| 10 | 1030792151040 |
| 11 | 16492674416640 |
| 12 | 263882790666240 |
| 13 | 4222124650659840 |
| 14 | 67553994410557440 |
| 15 | 1080863910568919040 |
| 16 | 17293822569102704640 |
| 17 | 276701161105643274240 |
| 18 | 4427218577690292387840 |
[1,15,240,3840,61440,983040,15728640,251658240, 4026531840,64424509440,1030792151040, 16492674416640,263882790666240,4222124650659840, 67553994410557440,1080863910568919040, 17293822569102704640,276701161105643274240, 4427218577690292387840] |