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Search: id:A046759
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| A046759 |
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Economical numbers: write n as a product of primes raised to powers, let D(n) = number of digits in product, l(n) = number of digits in n; sequence gives n such that D(n)<l(n). |
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5
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| 125, 128, 243, 256, 343, 512, 625, 729, 1024, 1029, 1215, 1250, 1280, 1331, 1369, 1458, 1536, 1681, 1701, 1715, 1792, 1849, 1875, 2048, 2187, 2197, 2209, 2401, 2560, 2809, 3125, 3481, 3584, 3645, 3721, 4096, 4374, 4375, 4489, 4802, 4913
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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C. K. Caldwell, The Prime Glossary, economical number
J.-M. De Koninck and F. Luca, On strings of consecutive economical numbers of arbitrary length
J.-P. Delahaye, Les chasseurs de nombres premiers
R. G. E. Pinch, Economical numbers.
R. G. E. Pinch, Economical numbers
W. Schneider, Economical Numbers
G. Villemin's Almanach of Numbers, Nombres Economes
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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EXAMPLE
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For n=125=5^3, l(n)=3 but D(n)=2.
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CROSSREFS
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Cf. A046758, A046760.
Sequence in context: A028939 A080538 A104233 this_sequence A115938 A126895 A069656
Adjacent sequences: A046756 A046757 A046758 this_sequence A046760 A046761 A046762
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KEYWORD
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nonn,nice,base,easy
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AUTHOR
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njas
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EXTENSIONS
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More terms from Eric Weisstein (eric(AT)weisstein.com)
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