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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 26 |
| 4 | 398 |
| 5 | 8604 |
| 6 | 239296 |
| 7 | 8135504 |
| 8 | 326921192 |
| 9 | 15159790680 |
| 10 | 796766681184 |
| 11 | 46805302872624 |
| 12 | 3039065898588144 |
| 13 | 216125148650657232 |
| 14 | 16706734205424667296 |
| 15 | 1394789126514873632832 |
| 16 | 125073511937467759505760 |
| 17 | 11989203887017099078716384 |
| 18 | 1223407961244225521367780096 |
[1,3,26,398,8604,239296,8135504,326921192, 15159790680,796766681184,46805302872624, 3039065898588144,216125148650657232, 16706734205424667296,1394789126514873632832, 125073511937467759505760, 11989203887017099078716384, 1223407961244225521367780096] |