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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 15 |
| 2 | -112 |
| 3 | 1680 |
| 4 | -31472 |
| 5 | 660240 |
| 6 | -14839664 |
| 7 | 349414800 |
| 8 | -8507710960 |
| 9 | 212459830800 |
| 10 | -5411770287728 |
| 11 | 140059532123280 |
| 12 | -3672503890520304 |
| 13 | 97354865146790160 |
| 14 | -2604834063375041904 |
| 15 | 70252635819008699280 |
| 16 | -1907877108652806790128 |
| 17 | 52128195213064060918800 |
| 18 | -1431935470768717669608560 |
[1,15,-112,1680,-31472,660240,-14839664,349414800, -8507710960,212459830800,-5411770287728, 140059532123280,-3672503890520304, 97354865146790160,-2604834063375041904, 70252635819008699280,-1907877108652806790128, 52128195213064060918800, -1431935470768717669608560] |