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Search: id:A067497
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| A067497 |
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Smallest power of 2 with n+1 digits (n>=0). Also n such that 1 is the first digit of 2^n. |
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+0
3
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| 0, 4, 7, 10, 14, 17, 20, 24, 27, 30, 34, 37, 40, 44, 47, 50, 54, 57, 60, 64, 67, 70, 74, 77, 80, 84, 87, 90, 94, 97, 100, 103, 107, 110, 113, 117, 120, 123, 127, 130, 133, 137, 140, 143, 147, 150, 153, 157, 160, 163, 167, 170, 173, 177, 180, 183, 187, 190, 193, 196
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n) = ceil(n*log[2](10)). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Jun 20 2002
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MATHEMATICA
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a[n_] := Block[{k = 0}, While[ Floor[Log[10, 2^k] + 1] < n, k++ ]; k]; Table[ a[n], {n, 1, 61}]
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PROGRAM
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(PARI) for(n=0, 500, if(floor(2^n/10^(floor(n*log(2)/log(10))))==1, print1(n, ", ")))
(PARI) s=0, for(n=0, 200, l=length(Str(2^n)), if(l>s, print1(n, ", "), s=l)) %Y A067497 Cf. A067480, A000079.
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CROSSREFS
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Cf. A067480, A000079.
Sequence in context: A125620 A062389 A080600 this_sequence A123384 A138813 A133497
Adjacent sequences: A067494 A067495 A067496 this_sequence A067498 A067499 A067500
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KEYWORD
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base,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 22 2002
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EXTENSIONS
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Additional comments from Lekraj Beedassy (blekraj(AT)yahoo.com), Jun 20 2002 and from Rick Shephard, Jun 27 2002
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