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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 20 |
| 3 | 88 |
| 4 | 336 |
| 5 | 1376 |
| 6 | 5440 |
| 7 | 21888 |
| 8 | 87296 |
| 9 | 349696 |
| 10 | 1397760 |
| 11 | 5593088 |
| 12 | 22368256 |
| 13 | 89481216 |
| 14 | 357908480 |
| 15 | 1431666688 |
| 16 | 5726601216 |
| 17 | 22906535936 |
| 18 | 91625881600 |
| 19 | 366504050688 |
| 20 | 1466015154176 |
| 21 | 5864062713856 |
| 22 | 23456246661120 |
| 23 | 93824995033088 |
| 24 | 375299963355136 |
| 25 | 1501199886974976 |
| 26 | 6004799480791040 |
| 27 | 24019198057381888 |
[1,6,20,88,336,1376,5440,21888,87296,349696, 1397760,5593088,22368256,89481216,357908480, 1431666688,5726601216,22906535936,91625881600, 366504050688,1466015154176,5864062713856, 23456246661120,93824995033088,375299963355136, 1501199886974976,6004799480791040, 24019198057381888] |