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A131537
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Least power of 2 having exactly n consecutive 3's in its decimal representation.
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0
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5, 25, 83, 219, 221, 2270, 11020, 18843, 192915, 271978, 743748, 1039315, 13873203, 14060685
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OFFSET
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1,1
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COMMENTS
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No more terms < 28*10^6.
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LINKS
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Table of n, a(n) for n=1..14.
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EXAMPLE
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a(3)=83 because 2^83(i.e. 9671406556917033397649408) is the smallest power of 2 to contain a run of 3 consecutive threes in its decimal form.
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MATHEMATICA
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a = ""; Do[ a = StringJoin[a, "3"]; b = StringJoin[a, "3"]; k = 1; While[ StringPosition[ ToString[2^k], a] == {} || StringPosition[ ToString[2^k], b] != {}, k++ ]; Print[k], {n, 1, 9} ]
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CROSSREFS
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Sequence in context: A062989 A122679 A147114 * A147122 A051229 A058919
Adjacent sequences: A131534 A131535 A131536 * A131538 A131539 A131540
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KEYWORD
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more,nonn,base
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AUTHOR
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Shyam Sunder Gupta (guptass(AT)rediffmail.com), Aug 26 2007
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EXTENSIONS
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3 more terms from Sean A. Irvine, Jul 19 2010
a(13)-a(14) from Lars Blomberg, Jan 24 2013
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STATUS
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approved
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