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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 56 |
| 3 | 448 |
| 4 | 3584 |
| 5 | 28672 |
| 6 | 229376 |
| 7 | 1835008 |
| 8 | 14680064 |
| 9 | 117440512 |
| 10 | 939524096 |
| 11 | 7516192768 |
| 12 | 60129542144 |
| 13 | 481036337152 |
| 14 | 3848290697216 |
| 15 | 30786325577728 |
| 16 | 246290604621824 |
| 17 | 1970324836974592 |
| 18 | 15762598695796736 |
| 19 | 126100789566373888 |
| 20 | 1008806316530991104 |
[1,7,56,448,3584,28672,229376,1835008,14680064, 117440512,939524096,7516192768,60129542144, 481036337152,3848290697216,30786325577728, 246290604621824,1970324836974592, 15762598695796736,126100789566373888, 1008806316530991104] |