cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A079411 a(1)=1, a(n) = n - a(a(ceiling(n/2))).

Original entry on oeis.org

1, 1, 2, 3, 4, 5, 5, 6, 6, 7, 7, 8, 9, 10, 10, 11, 12, 13, 14, 15, 16, 17, 17, 18, 19, 20, 20, 21, 22, 23, 24, 25, 25, 26, 26, 27, 27, 28, 29, 30, 30, 31, 31, 32, 33, 34, 34, 35, 35, 36, 36, 37, 38, 39, 39, 40, 40, 41, 42, 43, 43, 44, 44, 45, 46, 47, 47, 48, 49, 50, 51, 52, 53, 54
Offset: 1

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Author

Benoit Cloitre, Feb 16 2003

Keywords

Crossrefs

Cf. A076895.

Programs

  • Magma
    [n eq 1 select 1 else n-Self(Self(Ceiling(n/2))): n in [1..80]]; // Vincenzo Librandi, Oct 25 2017
  • Maple
    f:= proc(n) option remember;
      n - procname(procname(ceil(n/2)))
    end proc:
    f(1):= 1:
    seq(f(n),n=1..100); # Robert Israel, Oct 24 2017
  • Mathematica
    Fold[Append[#1, #2 - #1[[#1[[Ceiling[#2/2] ]] ]] ] &, {1}, Range[2, 74]] (* Michael De Vlieger, Oct 24 2017 *)
  • PARI
    a(n)=if(n<2,1,n-a(a(ceil(n/2))))
    

Formula

a(n) is asymptotic to n*(sqrt(3)-1); conjecture: (a(n)-n*(sqrt(3)-1))/log(n) is bounded.