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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 42 |
| 3 | 0 |
| 4 | 7676 |
| 5 | 0 |
| 6 | 1879040 |
| 7 | 0 |
| 8 | 489300384 |
| 9 | 0 |
| 10 | 129127695440 |
| 11 | 0 |
| 12 | 34175930646380 |
| 13 | 0 |
| 14 | 9050948918328308 |
| 15 | 0 |
| 16 | 2397326535775801848 |
| 17 | 0 |
| 18 | 634999208667955702740 |
| 19 | 0 |
| 20 | 168198450029830487388264 |
| 21 | 0 |
| 22 | 44552431219619052902569084 |
| 23 | 0 |
[0,42,0,7676,0,1879040,0,489300384,0,129127695440, 0,34175930646380,0,9050948918328308,0, 2397326535775801848,0,634999208667955702740,0, 168198450029830487388264,0, 44552431219619052902569084,0] |