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Search: id:A063762
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| A063762 |
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Sqrt(n)-rough nonprimes: largest prime factor of n (A006530) >= sqrt(n). |
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+0
4
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| 4, 6, 9, 10, 14, 15, 20, 21, 22, 25, 26, 28, 33, 34, 35, 38, 39, 42, 44, 46, 49, 51, 52, 55, 57, 58, 62, 65, 66, 68, 69, 74, 76, 77, 78, 82, 85, 86, 87, 88, 91, 92, 93, 94, 95, 99, 102, 104, 106, 110, 111, 114, 115, 116, 117, 118, 119, 121, 122, 123, 124, 129, 130, 133
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A positive integer is called y-rough if all its prime factors are >= y.
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REFERENCES
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D. H. Greene and D. E. Knuth, Mathematics for the Analysis of Algorithms; see pp. 95-98.
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
Beeler, M., Gosper, R. W. and Schroeppel, R., HAKMEM, ITEM 29
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MATHEMATICA
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Select[ Range[ 2, 150 ], !PrimeQ[ # ] && FactorInteger[ # ] [ [ -1, 1 ] ] >= Sqrt[ # ] & ]
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PROGRAM
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(PARI) { n=0; for (m=2, 10^9, f=vecmax(component(factor(m), 1)); if(!isprime(m) && f^2 >= m, write("b063762.txt", n++, " ", m); if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 30 2009]
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CROSSREFS
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Cf. A063538, A063539, A063763.
Adjacent sequences: A063759 A063760 A063761 this_sequence A063763 A063764 A063765
Sequence in context: A010428 A028260 A085155 this_sequence A001358 A108764 A129336
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 14 2001
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