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| n | a(n) |
|---|---|
| 1 | 16 |
| 2 | 72 |
| 3 | 384 |
| 4 | 1864 |
| 5 | 8720 |
| 6 | 40064 |
| 7 | 180992 |
| 8 | 805416 |
| 9 | 3542720 |
| 10 | 15437280 |
| 11 | 66739168 |
| 12 | 286614344 |
| 13 | 1223894208 |
| 14 | 5200593136 |
| 15 | 22003683264 |
| 16 | 92745730384 |
| 17 | 389613088944 |
| 18 | 1631810452416 |
| 19 | 6816075114112 |
| 20 | 28401442383848 |
[16,72,384,1864,8720,40064,180992,805416,3542720, 15437280,66739168,286614344,1223894208,5200593136, 22003683264,92745730384,389613088944, 1631810452416,6816075114112,28401442383848] |