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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 1 |
| 5 | 70 |
| 6 | 0 |
| 7 | 1 |
| 8 | 990 |
| 9 | 34650 |
| 10 | 0 |
| 11 | 1 |
| 12 | 16510 |
| 13 | 2702700 |
| 14 | 63063000 |
| 15 | 0 |
| 16 | 1 |
| 17 | 261630 |
| 18 | 213519150 |
| 19 | 17459442000 |
| 20 | 305540235000 |
| 21 | 0 |
| 22 | 1 |
| 23 | 4196350 |
| 24 | 17651304000 |
| 25 | 4350310965000 |
| 26 | 231905038365000 |
| 27 | 3246670537110000 |
[1,0,1,0,1,70,0,1,990,34650,0,1,16510,2702700, 63063000,0,1,261630,213519150,17459442000, 305540235000,0,1,4196350,17651304000, 4350310965000,231905038365000,3246670537110000] |