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Search: id:A071823
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| A071823 |
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Number of x with largest prime factor of the form 4k+3 less than or equal to n. |
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+0
1
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| 0, 1, 1, 1, 2, 3, 3, 4, 4, 5, 6, 6, 7, 7, 7, 7, 8, 9, 9, 10, 11, 12, 13, 13, 13, 14, 15, 15, 15, 16, 16, 17, 17, 18, 19, 19, 20, 20, 20, 20, 21, 22, 23, 23, 24, 25, 26, 27, 27, 27, 27, 27, 28, 29, 30, 31, 31, 32, 32, 32, 33, 34, 34, 34, 35, 36, 36, 37, 38, 39, 40, 40, 40, 40, 41
(list; graph; listen)
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OFFSET
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1,5
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COMMENT
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Conjecture : for n > 1000 a(n) - n/2 > sqrt(n)
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PROGRAM
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(PARI) for(n=2, 200, print1(sum(i=2, n, if((component(component(factor(i), 1), omega(i))-3)%4, 0, 1)), ", "))
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CROSSREFS
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Adjacent sequences: A071820 A071821 A071822 this_sequence A071824 A071825 A071826
Sequence in context: A091374 A065603 A084242 this_sequence A139338 A057355 A073869
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 07 2002
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