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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 18 |
| 4 | 284 |
| 5 | 7280 |
| 6 | 273246 |
| 7 | 14144592 |
| 8 | 965491288 |
| 9 | 84027112704 |
| 10 | 9081387766810 |
| 11 | 1193283000239616 |
| 12 | 187340544144604212 |
| 13 | 34633340434838499328 |
| 14 | 7446726867419368499894 |
| 15 | 1842612127654047957411840 |
| 16 | 519870106084045866346942256 |
| 17 | 165896395346243470375430193152 |
| 18 | 59450668490817059243377908811698 |
| 19 | 23773400714993519201980928470155264 |
[1,2,18,284,7280,273246,14144592,965491288, 84027112704,9081387766810,1193283000239616, 187340544144604212,34633340434838499328, 7446726867419368499894,1842612127654047957411840, 519870106084045866346942256, 165896395346243470375430193152, 59450668490817059243377908811698, 23773400714993519201980928470155264] |