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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 63 |
| 4 | 624 |
| 5 | 7775 |
| 6 | 117648 |
| 7 | 2097151 |
| 8 | 43046720 |
| 9 | 999999999 |
| 10 | 25937424600 |
| 11 | 743008370687 |
| 12 | 23298085122480 |
| 13 | 793714773254143 |
| 14 | 29192926025390624 |
| 15 | 1152921504606846975 |
| 16 | 48661191875666868480 |
| 17 | 2185911559738696531967 |
| 18 | 104127350297911241532840 |
| 19 | 5242879999999999999999999 |
| 20 | 278218429446951548637196400 |
| 21 | 15519448971100888972574851071 |
[0,1,8,63,624,7775,117648,2097151,43046720, 999999999,25937424600,743008370687,23298085122480, 793714773254143,29192926025390624, 1152921504606846975,48661191875666868480, 2185911559738696531967,104127350297911241532840, 5242879999999999999999999, 278218429446951548637196400, 15519448971100888972574851071] |