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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 27 |
| 4 | 171 |
| 5 | 1077 |
| 6 | 6963 |
| 7 | 45523 |
| 8 | 300417 |
| 9 | 1995897 |
| 10 | 13332697 |
| 11 | 89461271 |
| 12 | 602525231 |
| 13 | 4070925653 |
| 14 | 27580062519 |
| 15 | 187294750351 |
| 16 | 1274550544383 |
| 17 | 8689294370837 |
| 18 | 59336253329567 |
| 19 | 405779196651853 |
| 20 | 2778627840692687 |
| 21 | 19049684072515863 |
[1,5,27,171,1077,6963,45523,300417,1995897, 13332697,89461271,602525231,4070925653, 27580062519,187294750351,1274550544383, 8689294370837,59336253329567,405779196651853, 2778627840692687,19049684072515863] |