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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 4 |
| 3 | 8 |
| 4 | 48 |
| 5 | 160 |
| 6 | 704 |
| 7 | 2688 |
| 8 | 11008 |
| 9 | 43520 |
| 10 | 175104 |
| 11 | 698368 |
| 12 | 2797568 |
| 13 | 11182080 |
| 14 | 44744704 |
| 15 | 178946048 |
| 16 | 715849728 |
| 17 | 2863267840 |
| 18 | 11453333504 |
| 19 | 45812809728 |
| 20 | 183252287488 |
| 21 | 733007052800 |
| 22 | 2932032405504 |
| 23 | 11728121233408 |
[1,0,4,8,48,160,704,2688,11008,43520,175104, 698368,2797568,11182080,44744704,178946048, 715849728,2863267840,11453333504,45812809728, 183252287488,733007052800,2932032405504, 11728121233408] |