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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 10 |
| 3 | 42 |
| 4 | 248 |
| 5 | 2290 |
| 6 | 31042 |
| 7 | 641376 |
| 8 | 19753266 |
| 9 | 918924546 |
| 10 | 64065187024 |
| 11 | 6724991990090 |
| 12 | 1059952700132050 |
| 13 | 251257954485037072 |
| 14 | 89488725743024413554 |
| 15 | 47916300899545924260762 |
| 16 | 38558096411377540692559456 |
[4,10,42,248,2290,31042,641376,19753266,918924546, 64065187024,6724991990090,1059952700132050, 251257954485037072,89488725743024413554, 47916300899545924260762, 38558096411377540692559456] |