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A217178
a(n) is the number of digits in the decimal representation of the smallest power of n that contains three consecutive identical digits.
1
8, 16, 8, 35, 4, 27, 8, 16, 4, 9, 19, 28, 17, 28, 8, 15, 8, 12, 4, 15, 10, 21, 20, 35, 16, 16, 15, 8, 5, 11, 13, 16, 16, 28, 15, 24, 4, 20, 5, 23, 7, 12, 20, 30, 20, 14, 29, 29, 6, 26, 18, 13, 20, 44, 42, 15, 20, 18, 6, 25, 20, 33, 8, 13, 17, 24, 13, 23, 6, 21
OFFSET
2,1
COMMENTS
Number of digits in n^k is equal to floor(1 + k*log_10(n)).
MATHEMATICA
Table[k = 1; While[d = IntegerDigits[n^k]; ! MemberQ[Partition[Differences[d], 2, 1], {0, 0}], k++]; Length[d], {n, 2, 100}] (* T. D. Noe, Oct 03 2012 *)
spn3[n_]:=Module[{p=1}, While[SequenceCount[IntegerDigits[n^p], {x_, x_, x_}]<1, p++]; IntegerLength[n^p]]; Array[spn3, 80, 2] (* Harvey P. Dale, Nov 10 2022 *)
CROSSREFS
Sequence in context: A174256 A037239 A205869 * A103699 A238835 A040056
KEYWORD
nonn,base
AUTHOR
V. Raman, Sep 27 2012
STATUS
approved