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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 15 |
| 3 | 45 |
| 4 | 405 |
| 5 | 2025 |
| 6 | 6075 |
| 7 | 91125 |
| 8 | 1549125 |
| 9 | 13942125 |
| 10 | 23236875 |
| 11 | 534448125 |
| 12 | 64133775 |
| 13 | 1731611925 |
| 14 | 50216745825 |
| 15 | 753251187375 |
| 16 | 2259753562125 |
| 17 | 7683162111225 |
| 18 | 69148459001025 |
| 19 | 207445377003075 |
| 20 | 1037226885015375 |
| 21 | 14866918685220375 |
| 22 | 669011340834916875 |
[3,15,45,405,2025,6075,91125,1549125,13942125, 23236875,534448125,64133775,1731611925, 50216745825,753251187375,2259753562125, 7683162111225,69148459001025,207445377003075, 1037226885015375,14866918685220375, 669011340834916875] |