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| n | a(n) |
|---|---|
| 1 | 8 |
| 2 | 40 |
| 3 | 216 |
| 4 | 1152 |
| 5 | 6160 |
| 6 | 32928 |
| 7 | 176032 |
| 8 | 941056 |
| 9 | 5030848 |
| 10 | 26894720 |
| 11 | 143778176 |
| 12 | 768632832 |
| 13 | 4109082880 |
| 14 | 21967006208 |
| 15 | 117434808832 |
| 16 | 627802177536 |
| 17 | 3356207397888 |
| 18 | 17942161561600 |
| 19 | 95918137153536 |
| 20 | 512774840614912 |
[8,40,216,1152,6160,32928,176032,941056,5030848, 26894720,143778176,768632832,4109082880, 21967006208,117434808832,627802177536, 3356207397888,17942161561600,95918137153536, 512774840614912] |