This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A103128 n appears 2 * ceiling(n/2) times. 6
 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 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = floor(sqrt(2n-1)). 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, 1, 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: A071626 A182008 A106457 * A156080 A271058 A107320 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 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.