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A215727
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a(n) is the smallest m for which 3^m contains n consecutive identical digits.
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17
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0, 11, 32, 33, 274, 538, 2124, 7720, 22791, 107187, 107187, 639226, 5756979, 8885853, 68353787, 78927180, 78927180
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OFFSET
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1,2
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COMMENTS
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3^(a(16)+1) contains exactly 16 consecutive 3's. - Bert Dobbelaere, Mar 20 2019
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LINKS
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EXAMPLE
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3^11 = 177147, which has two digits in a row.
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MATHEMATICA
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A215727[n_] := Module[{m = 0 , t}, t = Table[i, {i, 0, 9}, {n}];
While[True, If[ContainsAny[Subsequences[IntegerDigits[3^m], {n}], t], Return[m], m++]]; m]; Table[A215727[n], {n, 1, 14}] (* Robert Price, Oct 16 2018 *)
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PROG
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(Python)
l, x = [str(d)*n for d in range(10)], 1
for m in range(10**9):
s = str(x)
for k in l:
if k in s:
return m
x *= 3
return 'search limit reached'
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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