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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 16 |
| 5 | 40 |
| 6 | 80 |
| 7 | 192 |
| 8 | 400 |
| 9 | 936 |
| 10 | 1984 |
| 11 | 4576 |
| 12 | 9824 |
| 13 | 22408 |
| 14 | 48560 |
| 15 | 109888 |
| 16 | 239728 |
| 17 | 539432 |
| 18 | 1182432 |
| 19 | 2649952 |
| 20 | 5828544 |
| 21 | 13024648 |
| 22 | 28717648 |
| 23 | 64040768 |
| 24 | 141448528 |
| 25 | 314965928 |
| 26 | 696544000 |
| 27 | 1549366240 |
| 28 | 3429474848 |
| 29 | 7622621832 |
| 30 | 16883244016 |
[2,4,8,16,40,80,192,400,936,1984,4576,9824,22408, 48560,109888,239728,539432,1182432,2649952, 5828544,13024648,28717648,64040768,141448528, 314965928,696544000,1549366240,3429474848, 7622621832,16883244016] |