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 A176095 a(n) = n - phi(2*n), where phi() is the Euler totient A000010(). 2
 0, 0, 1, 0, 1, 2, 1, 0, 3, 2, 1, 4, 1, 2, 7, 0, 1, 6, 1, 4, 9, 2, 1, 8, 5, 2, 9, 4, 1, 14, 1, 0, 13, 2, 11, 12, 1, 2, 15, 8, 1, 18, 1, 4, 21, 2, 1, 16, 7, 10, 19, 4, 1, 18, 15, 8, 21, 2, 1, 28, 1, 2, 27, 0, 17, 26, 1, 4, 25, 22, 1, 24, 1, 2, 35, 4, 17, 30, 1, 16, 27, 2, 1, 36, 21, 2, 31, 8, 1, 42, 19 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 REFERENCES M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 840. T. M. Apostol, Introduction to Analytic Number Theory, Springer-Verlag, 1976, page 24. LINKS FORMULA a(n) = n - A062570(n). a(2^k) = 0, k >= 0. - Michel Lagneau, Dec 17 2010 a(A000040(k)) = 1, k >= 1. - Michel Lagneau, Dec 17 2010 a(2^m*A000040(k)) = 2^m, m >= 1, k >= 2. - Michel Lagneau, Dec 17 2010 EXAMPLE a(1) = 1 - phi(2) = 0; a(2) = 2 - phi(2*2) = 2 - 2 = 0; a(3) = 3 - phi(2*3) = 3 - 2 = 1; If n = (2^m)*p, with m = 3 and p = 7, then n = 2^3 * 7 = 56, and a(56) = 2^3 = 8. MAPLE A176095 := proc(n)     n-numtheory[phi](2*n) ; end proc: seq(A176095(n), n=1..60) ; MATHEMATICA Table[n-EulerPhi[2n], {n, 0, 100}] (* Harvey P. Dale, Jul 24 2011 *) CROSSREFS Cf. A000010. Sequence in context: A022336 A019586 A257962 * A295508 A260672 A063942 Adjacent sequences:  A176092 A176093 A176094 * A176096 A176097 A176098 KEYWORD nonn AUTHOR Michel Lagneau, Apr 08 2010 EXTENSIONS Offset corrected; entry corrected and edited by Michel Lagneau, Apr 25 2010 STATUS approved

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Last modified April 11 23:19 EDT 2021. Contains 342895 sequences. (Running on oeis4.)