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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 28 |
| 6 | 56 |
| 7 | 256 |
| 8 | 656 |
| 9 | 2480 |
| 10 | 6688 |
| 11 | 30736 |
| 12 | 73984 |
| 13 | 366560 |
| 14 | 1006720 |
| 15 | 3966976 |
| 16 | 12738560 |
| 17 | 58427648 |
| 18 | 148069632 |
| 19 | 764473600 |
| 20 | 2133585664 |
| 21 | 8939502080 |
| 22 | 28705390592 |
| 23 | 136987259648 |
| 24 | 356634376704 |
| 25 | 1780025034240 |
| 26 | 5455065263104 |
| 27 | 23215437079552 |
| 28 | 73123382895616 |
[1,2,4,8,28,56,256,656,2480,6688,30736,73984, 366560,1006720,3966976,12738560,58427648, 148069632,764473600,2133585664,8939502080, 28705390592,136987259648,356634376704, 1780025034240,5455065263104,23215437079552, 73123382895616] |