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| n | a(n) |
|---|---|
| 1 | 240 |
| 2 | 1096 |
| 3 | 4192 |
| 4 | 19120 |
| 5 | 74496 |
| 6 | 339328 |
| 7 | 1344640 |
| 8 | 6116416 |
| 9 | 24606720 |
| 10 | 111778816 |
| 11 | 455721472 |
| 12 | 2067523840 |
| 13 | 8527405056 |
| 14 | 38641758208 |
| 15 | 160972933120 |
| 16 | 728673166336 |
| 17 | 3061520302080 |
| 18 | 13845560836096 |
| 19 | 58597910781952 |
| 20 | 264790110146560 |
[240,1096,4192,19120,74496,339328,1344640,6116416, 24606720,111778816,455721472,2067523840, 8527405056,38641758208,160972933120,728673166336, 3061520302080,13845560836096,58597910781952, 264790110146560] |