| 1, 2, 3, 5, 7, 10, 11, 13, 14, 15, 16, 17, 19, 21, 23, 25, 27, 29, 31, 32, 35, 37, 41, 43, 47, 49, 53, 59, 61, 64, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 105, 106, 107, 109, 111, 112, 113, 115, 118, 119, 121, 122, 123, 127, 129, 131, 133, 134, 135, 137, 139
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Write n as product of primes raised to powers, let D(n) = A050252 = total number of digits in product representation (number of digits in all the primes plus number of digits in all the exponents that are greater than 1) and l(n) = number of digits in n; sequence gives n such that D(n)=l(n).
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LINKS
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J. P. Delahaye, "Primes Hunters", Economical and Prodigal Numbers (Text in French)
R. G. E. Pinch, Economical numbers.
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. A046759, A046760, A050252, A073048.
Sequence in context: A076387 A163975 A125975 this_sequence A121232 A122428 A087246
Adjacent sequences: A046755 A046756 A046757 this_sequence A046759 A046760 A046761
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KEYWORD
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nonn,base,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Eric Weisstein (eric(AT)weisstein.com)
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