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| n | a(n) |
|---|---|
| 1 | 48 |
| 2 | 328 |
| 3 | 2360 |
| 4 | 17280 |
| 5 | 127464 |
| 6 | 943016 |
| 7 | 6985008 |
| 8 | 51763176 |
| 9 | 383669400 |
| 10 | 2843977792 |
| 11 | 21081830152 |
| 12 | 156277203016 |
| 13 | 1158470626096 |
| 14 | 8587668090888 |
| 15 | 63659878472312 |
| 16 | 471907077858304 |
| 17 | 3498220894515624 |
| 18 | 25932117973637736 |
| 19 | 192233359691316016 |
[48,328,2360,17280,127464,943016,6985008,51763176, 383669400,2843977792,21081830152,156277203016, 1158470626096,8587668090888,63659878472312, 471907077858304,3498220894515624, 25932117973637736,192233359691316016] |