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 A103128 a(n) = floor(sqrt(2n-1)). 7
 1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS n appears 2 * ceiling(n/2) times. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA From Robert Israel, Sep 12 2016: (Start) a(n+1) = a(n)+1 for n in A007590, otherwise a(n+1) = a(n). G.f.: x*Theta3(x^2)/(2*(1-x)) + sqrt(x)*Theta2(x^2)/(2*(1-x)) - x/(2*(1-x)), where Theta2 and Theta3 are Jacobi Theta functions. (End) MAPLE seq(floor(sqrt(2*n-1)), n=1..100); # Robert Israel, Sep 12 2016 MATHEMATICA Table[Floor[Sqrt[2n-1]], {n, 100}] (* Mohammad K. Azarian, Jun 15 2016 *) PROG (Haskell) a103128 = a000196 . (subtract 1) . (* 2) -- Reinhard Zumkeller, Feb 12 2012 CROSSREFS Cf. A172471, A000196, A005408, A007590. Sequence in context: A182008 A106457 A331852 * A156080 A334233 A271058 Adjacent sequences:  A103125 A103126 A103127 * A103129 A103130 A103131 KEYWORD easy,nonn AUTHOR Giovanni Teofilatto, Mar 17 2005 EXTENSIONS Edited by Franklin T. Adams-Watters, Apr 20 2010 New name from Wesley Ivan Hurt, Nov 26 2020 STATUS approved

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Last modified June 13 05:05 EDT 2021. Contains 344980 sequences. (Running on oeis4.)