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A155699
Last n-digit string to appear as the first n digits of a positive power of 2.
1
9, 97, 982, 7629, 95367, 997432, 9313225, 95367431
OFFSET
1,1
COMMENTS
a(n) = floor(f(n) / 10^(floor(log_10(f(n))) - n + 1)) where f(n) = 2^A155700(n). (I.e., a(n) is the number composed of the first n digits of 2^A155700(n).)
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 (at 2^279 = 9.713...*10^83), so a(2) = 97.
CROSSREFS
Sequence in context: A232229 A240780 A236672 * A230620 A155601 A241771
KEYWORD
nonn,base,more
AUTHOR
Jon E. Schoenfield, Jan 25 2009
STATUS
approved