|
EXAMPLE
|
The powers of 2 having at least 2 digits are 16, 32, 64, 128, 256, ...; discarding all but their first 2 digits yields the sequence 16, 32, 64, 12, 25, ..., in which all 90 of the possible 2-digit numbers (10 through 99) eventually appear; the last to appear is 97, which appears at 2^279 = 9.713...*10^83), so a(2) = 279.
|