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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 189 |
| 5 | 189 |
| 6 | 12474 |
| 7 | 43659 |
| 8 | 4191264 |
| 9 | 37721376 |
| 10 | 120406632192 |
| 11 | 220745492352 |
| 12 | 974812094226432 |
| 13 | 78959779632340992 |
| 14 | 4421747659411095552 |
| 15 | 1658155372279160832 |
| 16 | 49948354512933617664 |
| 17 | 1519878479474057051897856 |
| 18 | 15633035788876015390949376 |
[1,1,1,1,189,189,12474,43659,4191264,37721376, 120406632192,220745492352,974812094226432, 78959779632340992,4421747659411095552, 1658155372279160832,49948354512933617664, 1519878479474057051897856, 15633035788876015390949376] |