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Search: id:A131536
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| A131536 |
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Least power of 2 having exactly n consecutive 2's in its decimal representation. |
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+0
1
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| 1, 51, 43, 692, 314, 2354, 8555, 13326, 81784, 279272
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(3)=43 because 2^43(i.e. 8796093022208) is the smallest power of 2 to contain a run of 3 consecutive twos in its decimal form.
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MATHEMATICA
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a = ""; Do[ a = StringJoin[a, "2"]; b = StringJoin[a, "2"]; k = 1; While[ StringPosition[ ToString[2^k], a] == {} || StringPosition[ ToString[2^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
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CROSSREFS
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Sequence in context: A087408 A160474 A033371 this_sequence A003912 A039932 A031959
Adjacent sequences: A131533 A131534 A131535 this_sequence A131537 A131538 A131539
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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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