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Search: id:A083182
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| A083182 |
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Greatest 3-brilliant number of size n. |
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2
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| 8, 98, 343, 9971, 99937, 912673, 9999707, 99999667, 991026973, 9999999467, 99999999007, 991921850317, 9999999994771, 99999999994117, 999730024299271, 9999999999997097, 99999999999992023, 999949000866995087
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Brilliant numbers, as defined by Peter Wallrodt, are numbers with two prime factors of the same length (in decimal notation). These numbers are generally used for cryptographic purposes and for testing the performance of prime factoring programs.
a(3n) will always be the cube of the greatest prime less than 10^n.
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LINKS
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Dario Alpern, Brilliant numbers
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EXAMPLE
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a(5) = 99937 = 37 * 37 * 73 and there is no greater number of five digits which has three prime factors, not necessarily different, of the same size in decimal notation.
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CROSSREFS
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Cf. A083128.
Sequence in context: A114425 A052127 A002506 this_sequence A116267 A116130 A116287
Adjacent sequences: A083179 A083180 A083181 this_sequence A083183 A083184 A083185
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KEYWORD
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nonn,base
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), May 11 2003
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