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A217185 a(n) is the number of digits in the decimal representation of the smallest power of 2 that contains n consecutive identical digits. 0
1, 5, 8, 13, 67, 293, 293, 2576, 12790, 12790, 81874, 312865, 520061, 2063822 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Number of digits in 2^k is equal to floor(1 + k*log_10(2)).

LINKS

Table of n, a(n) for n=1..14.

MATHEMATICA

k = 0; Join[{1}, Table[While[d = IntegerDigits[2^k]; prt = Partition[Differences[d], n - 1, 1]; ! MemberQ[prt, Table[0, {n - 1}]], k++]; Length[d], {n, 2, 8}]] (* T. D. Noe, Oct 03 2012 *)

CROSSREFS

Cf. A045875, A215732.

Sequence in context: A306943 A020736 A314469 * A160421 A249719 A314470

Adjacent sequences:  A217182 A217183 A217184 * A217186 A217187 A217188

KEYWORD

nonn,base

AUTHOR

V. Raman, Sep 27 2012

STATUS

approved

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Last modified September 18 09:22 EDT 2020. Contains 337166 sequences. (Running on oeis4.)