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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 16 |
| 3 | 82 |
| 4 | 410 |
| 5 | 2053 |
| 6 | 10266 |
| 7 | 51332 |
| 8 | 256660 |
| 9 | 1283303 |
| 10 | 6416516 |
| 11 | 32082582 |
| 12 | 160412910 |
| 13 | 802064553 |
| 14 | 4010322766 |
| 15 | 20051613832 |
| 16 | 100258069160 |
| 17 | 501290345803 |
| 18 | 2506451729016 |
| 19 | 12532258645082 |
| 20 | 62661293225410 |
| 21 | 313306466127053 |
[3,16,82,410,2053,10266,51332,256660,1283303, 6416516,32082582,160412910,802064553,4010322766, 20051613832,100258069160,501290345803, 2506451729016,12532258645082,62661293225410, 313306466127053] |