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| n | a(n) |
|---|---|
| 1 | 16 |
| 2 | 154 |
| 3 | 1240 |
| 4 | 9202 |
| 5 | 66016 |
| 6 | 466954 |
| 7 | 3283240 |
| 8 | 23026402 |
| 9 | 161316016 |
| 10 | 1129605754 |
| 11 | 7908421240 |
| 12 | 55362491602 |
| 13 | 387548070016 |
| 14 | 2712868376554 |
| 15 | 18990174295240 |
| 16 | 132931507044802 |
| 17 | 930521410248016 |
| 18 | 6513652454539354 |
| 19 | 45595574930185240 |
| 20 | 319169047756526002 |
[16,154,1240,9202,66016,466954,3283240,23026402, 161316016,1129605754,7908421240,55362491602, 387548070016,2712868376554,18990174295240, 132931507044802,930521410248016,6513652454539354, 45595574930185240,319169047756526002] |