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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 21 |
| 3 | 148 |
| 4 | 1039 |
| 5 | 7273 |
| 6 | 50912 |
| 7 | 356387 |
| 8 | 2494709 |
| 9 | 17462964 |
| 10 | 122240751 |
| 11 | 855685257 |
| 12 | 5989796800 |
| 13 | 41928577603 |
| 14 | 293500043221 |
| 15 | 2054500302548 |
| 16 | 14381502117839 |
| 17 | 100670514824873 |
| 18 | 704693603774112 |
| 19 | 4932855226418787 |
[3,21,148,1039,7273,50912,356387,2494709,17462964, 122240751,855685257,5989796800,41928577603, 293500043221,2054500302548,14381502117839, 100670514824873,704693603774112,4932855226418787] |