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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 8 |
| 3 | 16 |
| 4 | 64 |
| 5 | 512 |
| 6 | 8192 |
| 7 | 524288 |
| 8 | 268435456 |
| 9 | 4398046511104 |
| 10 | 9223372036854775808 |
| 11 | 19807040628566084398385987584 |
| 12 | 2787593149816327892691964784081045188247552 |
| 13 | 3291009114642412084309938365114701009965471731267159726697218048 |
[4,8,16,64,512,8192,524288,268435456, 4398046511104,9223372036854775808, 19807040628566084398385987584, 2787593149816327892691964784081045188247552, 32910091146424120843099383651147010099654717312671\ 59726697218048] |