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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 4 |
| 4 | 0 |
| 5 | -4 |
| 6 | 0 |
| 7 | 8 |
| 8 | 0 |
| 9 | -20 |
| 10 | 0 |
| 11 | 56 |
| 12 | 0 |
| 13 | -168 |
| 14 | 0 |
| 15 | 528 |
| 16 | 0 |
| 17 | -1716 |
| 18 | 0 |
| 19 | 5720 |
| 20 | 0 |
| 21 | -19448 |
| 22 | 0 |
| 23 | 67184 |
| 24 | 0 |
| 25 | -235144 |
| 26 | 0 |
| 27 | 832048 |
| 28 | 0 |
| 29 | -2971600 |
| 30 | 0 |
| 31 | 10697760 |
| 32 | 0 |
| 33 | -38779380 |
| 34 | 0 |
| 35 | 141430680 |
| 36 | 0 |
| 37 | -518579160 |
| 38 | 0 |
| 39 | 1910554800 |
| 40 | 0 |
| 41 | -7069052760 |
| 42 | 0 |
| 43 | 26256481680 |
| 44 | 0 |
| 45 | -97865068080 |
| 46 | 0 |
| 47 | 365930254560 |
| 48 | 0 |
[1,2,4,4,0,-4,0,8,0,-20,0,56,0,-168,0,528,0,-1716, 0,5720,0,-19448,0,67184,0,-235144,0,832048,0, -2971600,0,10697760,0,-38779380,0,141430680,0, -518579160,0,1910554800,0,-7069052760,0, 26256481680,0,-97865068080,0,365930254560,0] |