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| n | a(n) |
|---|---|
| 1 | 5 |
| 2 | 15 |
| 3 | 63 |
| 4 | 384 |
| 5 | 2393 |
| 6 | 13569 |
| 7 | 72744 |
| 8 | 393006 |
| 9 | 2206620 |
| 10 | 12731028 |
| 11 | 73789033 |
| 12 | 425385252 |
| 13 | 2445427072 |
| 14 | 14098065430 |
| 15 | 81698759400 |
| 16 | 475327637850 |
| 17 | 2770724256604 |
| 18 | 16165039535028 |
| 19 | 94402460826924 |
| 20 | 552050600817600 |
| 21 | 3233027830180059 |
[5,15,63,384,2393,13569,72744,393006,2206620, 12731028,73789033,425385252,2445427072, 14098065430,81698759400,475327637850, 2770724256604,16165039535028,94402460826924, 552050600817600,3233027830180059] |