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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 48 |
| 3 | 140 |
| 4 | 1132 |
| 5 | 6732 |
| 6 | 51884 |
| 7 | 381812 |
| 8 | 2783500 |
| 9 | 19762916 |
| 10 | 135821156 |
| 11 | 901633552 |
| 12 | 5803821376 |
| 13 | 36474619144 |
| 14 | 225357234996 |
| 15 | 1376605005684 |
| 16 | 8348102460156 |
[6,48,140,1132,6732,51884,381812,2783500,19762916, 135821156,901633552,5803821376,36474619144, 225357234996,1376605005684,8348102460156] |