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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 4 |
| 5 | 4 |
| 6 | 80 |
| 7 | 80 |
| 8 | 4752 |
| 9 | 4752 |
| 10 | 440192 |
| 11 | 440192 |
| 12 | 59245120 |
| 13 | 59245120 |
| 14 | 10930514688 |
| 15 | 10930514688 |
| 16 | 2649865335040 |
| 17 | 2649865335040 |
| 18 | 817154768973824 |
| 19 | 817154768973824 |
| 20 | 312426715251262464 |
| 21 | 312426715251262464 |
| 22 | 145060238642780180480 |
| 23 | 145060238642780180480 |
[1,1,0,0,4,4,80,80,4752,4752,440192,440192, 59245120,59245120,10930514688,10930514688, 2649865335040,2649865335040,817154768973824, 817154768973824,312426715251262464, 312426715251262464,145060238642780180480, 145060238642780180480] |