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| n | a(n) |
|---|---|
| 1 | -1 |
| 2 | -2 |
| 3 | 0 |
| 4 | 16 |
| 5 | 110 |
| 6 | 708 |
| 7 | 5026 |
| 8 | 40304 |
| 9 | 362862 |
| 10 | 3628780 |
| 11 | 39916778 |
| 12 | 479001576 |
| 13 | 6227020774 |
| 14 | 87178291172 |
| 15 | 1307674367970 |
| 16 | 20922789887968 |
| 17 | 355687428095966 |
| 18 | 6402373705727964 |
| 19 | 121645100408831962 |
| 20 | 2432902008176639960 |
| 21 | 51090942171709439958 |
| 22 | 1124000727777607679956 |
| 23 | 25852016738884976639954 |
| 24 | 620448401733239439359952 |
[-1,-2,0,16,110,708,5026,40304,362862,3628780, 39916778,479001576,6227020774,87178291172, 1307674367970,20922789887968,355687428095966, 6402373705727964,121645100408831962, 2432902008176639960,51090942171709439958, 1124000727777607679956,25852016738884976639954, 620448401733239439359952] |