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 A116568 Difference between n and the absolute value of the difference between number of nonprimes not exceeding n and number of primes not exceeding n. 1
 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; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS G. C. Greubel, Table of n, a(n) for n = 1..5000 FORMULA a(n) = n - Abs[A097454(n)]. EXAMPLE 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. MAPLE with(numtheory): seq(n-abs(n-2*pi(n)), n=1..73); MATHEMATICA Table[n-Abs[2*PrimePi[n]-n], {n, 80}] (* Harvey P. Dale, Oct 08 2015 *) PROG (PARI) for(n=1, 50, print1(n - abs(2*primepi(n) - n) , ", ")) \\ G. C. Greubel, Sep 20 2017 CROSSREFS Cf. A097454. Sequence in context: A179291 A004079 A096494 * A239933 A061106 A352928 Adjacent sequences: A116565 A116566 A116567 * A116569 A116570 A116571 KEYWORD nonn AUTHOR Roger L. Bagula, Mar 18 2006 EXTENSIONS Edited by N. J. A. Sloane, Apr 05 2006 STATUS approved

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Last modified August 10 00:01 EDT 2024. Contains 375044 sequences. (Running on oeis4.)