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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 13 |
| 3 | 60 |
| 4 | 251 |
| 5 | 1018 |
| 6 | 4089 |
| 7 | 16376 |
| 8 | 65527 |
| 9 | 262134 |
| 10 | 1048565 |
| 11 | 4194292 |
| 12 | 16777203 |
| 13 | 67108850 |
| 14 | 268435441 |
| 15 | 1073741808 |
| 16 | 4294967279 |
| 17 | 17179869166 |
| 18 | 68719476717 |
| 19 | 274877906924 |
| 20 | 1099511627755 |
| 21 | 4398046511082 |
| 22 | 17592186044393 |
| 23 | 70368744177640 |
| 24 | 281474976710631 |
| 25 | 1125899906842598 |
[2,13,60,251,1018,4089,16376,65527,262134,1048565, 4194292,16777203,67108850,268435441,1073741808, 4294967279,17179869166,68719476717,274877906924, 1099511627755,4398046511082,17592186044393, 70368744177640,281474976710631,1125899906842598] |