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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 6 |
| 3 | 47 |
| 4 | 385 |
| 5 | 3245 |
| 6 | 27346 |
| 7 | 230128 |
| 8 | 1936687 |
| 9 | 16300179 |
| 10 | 137192011 |
| 11 | 1154685911 |
| 12 | 9718495665 |
| 13 | 81796457512 |
| 14 | 688446233557 |
| 15 | 5794361407059 |
| 16 | 48768695462933 |
| 17 | 410465538968189 |
| 18 | 3454715318219146 |
| 19 | 29076881764570866 |
| 20 | 244727850397713496 |
[3,6,47,385,3245,27346,230128,1936687,16300179, 137192011,1154685911,9718495665,81796457512, 688446233557,5794361407059,48768695462933, 410465538968189,3454715318219146, 29076881764570866,244727850397713496] |