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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 4 |
| 3 | 6 |
| 4 | 128 |
| 5 | 610 |
| 6 | 12192 |
| 7 | 112154 |
| 8 | 2416416 |
| 9 | 34337538 |
| 10 | 827541200 |
| 11 | 16047333082 |
| 12 | 436958019984 |
| 13 | 10718568174626 |
| 14 | 329594991463584 |
| 15 | 9737689680629850 |
| 16 | 336439401299953472 |
| 17 | 11581626068262440194 |
| 18 | 446492838289046854320 |
| 19 | 17496904148975860376474 |
| 20 | 747070411957344952492080 |
[1,0,4,6,128,610,12192,112154,2416416,34337538, 827541200,16047333082,436958019984,10718568174626, 329594991463584,9737689680629850, 336439401299953472,11581626068262440194, 446492838289046854320,17496904148975860376474, 747070411957344952492080] |