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Search: id:A143907
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| A143907 |
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If n = product{primes p(k)|n} p(k)^b(n,p(k)), where p(k) is the kth prime that divides n (when these primes are listed from smallest to largest) and each b(n,p(k)) is a positive integer, then the sequence contains the non-prime-powers n such that p(k)^b(n,p(k)) < p(k+1) for all k, 1<=k<= -1 + number of distinct prime divisors of n. |
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2
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| 6, 10, 14, 15, 18, 20, 21, 22, 26, 28, 30, 33, 34, 35, 38, 39, 42, 44, 46, 50, 51, 52, 54, 55, 57, 58, 62, 65, 66, 68, 69, 70, 74, 75, 76, 77, 78, 82, 85, 86, 87, 88, 91, 92, 93, 94, 95, 98, 99, 100, 102, 104, 105, 106, 110, 111, 114, 115, 116, 117, 118, 119, 122, 123, 124
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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2900 is factored as 2^2 * 5^2 * 29^1. Since 2^2 < 5 and 5^2 < 29, then 2900 is in the sequence. On the other hand, 60 is factored as 2^2 * 3^1 * 5^1. Even though 3^1 < 5, 2^2 is not < 3. So 60 is not in the sequence.
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CROSSREFS
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Cf. A102308.
A057714 [From Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 06 2008]
Sequence in context: A085232 A085234 A057714 this_sequence A132982 A069169 A080364
Adjacent sequences: A143904 A143905 A143906 this_sequence A143908 A143909 A143910
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Sep 04 2008
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 06 2008
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