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Search: id:A131549
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| A131549 |
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Least power of 3 having exactly n consecutive 4's in its decimal representation. |
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+0
1
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| 5, 12, 55, 308, 510, 2340, 7286, 9670, 125406, 222961
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(3)=55 because 3^55(i.e. 174449211009120179071170507) is the smallest power of 3 to contain a run of 3 consecutive fours in its decimal form.
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MATHEMATICA
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a = ""; Do[ a = StringJoin[a, "4"]; b = StringJoin[a, "4"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
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CROSSREFS
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Sequence in context: A054661 A062978 A066961 this_sequence A111904 A015784 A129723
Adjacent sequences: A131546 A131547 A131548 this_sequence A131550 A131551 A131552
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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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