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Search: id:A116568
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| A116568 |
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Difference between n and the absolute value of the difference between number of nonprimes not exceeding n and number of primes not exceeding n. |
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+0
1
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| 0, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 10, 12, 12, 12, 12, 14, 14, 16, 16, 16, 16, 18, 18, 18, 18, 18, 18, 20, 20, 22, 22, 22, 22, 22, 22, 24, 24, 24, 24, 26, 26, 28, 28, 28, 28, 30, 30, 30, 30, 30, 30, 32, 32, 32, 32, 32, 32, 34, 34, 36, 36, 36, 36, 36, 36, 38, 38, 38, 38, 40, 40, 42
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n)=n-Abs[A097454(n)].
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EXAMPLE
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a(11)=10 because the nonprimes not exceeding 11 are 1,4,6,8,9 and 10, the primes not exceeding 11 are 2,3,5,7 and 11 and 11-abs(6-5)=10.
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MAPLE
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with(numtheory): seq(n-abs(n-2*pi(n)), n=1..73);
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CROSSREFS
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Cf. A097454.
Sequence in context: A079584 A004079 A096494 this_sequence A061106 A161764 A131055
Adjacent sequences: A116565 A116566 A116567 this_sequence A116569 A116570 A116571
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KEYWORD
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nonn
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Mar 18 2006
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Apr 05 2006
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