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A217186
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a(n) is the number of digits in the decimal representation of the smallest power of 3 that contains n consecutive identical digits.
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1
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1, 6, 16, 16, 131, 257, 1014, 3684, 10875, 51142, 51142, 304989
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OFFSET
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1,2
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COMMENTS
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Number of digits in 3^k is equal to floor(1 + k*log_10(3)).
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LINKS
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MATHEMATICA
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k = 0; Join[{1}, Table[While[d = IntegerDigits[3^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 *)
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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 len(s)
........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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