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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 8 |
| 3 | 38 |
| 4 | 176 |
| 5 | 816 |
| 6 | 3616 |
| 7 | 15362 |
| 8 | 63484 |
| 9 | 258180 |
| 10 | 1041120 |
| 11 | 4180554 |
| 12 | 16752240 |
| 13 | 67064038 |
| 14 | 268355784 |
| 15 | 1073601356 |
| 16 | 4294721316 |
| 17 | 17179440926 |
| 18 | 68718734848 |
| 19 | 274876627338 |
| 20 | 1099509429172 |
| 21 | 4398042746324 |
| 22 | 17592179617352 |
| 23 | 70368733235570 |
[2,8,38,176,816,3616,15362,63484,258180,1041120, 4180554,16752240,67064038,268355784,1073601356, 4294721316,17179440926,68718734848,274876627338, 1099509429172,4398042746324,17592179617352, 70368733235570] |