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.

Showing 1-2 of 2 results.

A014571 Consider the Morse-Thue sequence (A010060) as defining a binary constant and convert it to decimal.

Original entry on oeis.org

4, 1, 2, 4, 5, 4, 0, 3, 3, 6, 4, 0, 1, 0, 7, 5, 9, 7, 7, 8, 3, 3, 6, 1, 3, 6, 8, 2, 5, 8, 4, 5, 5, 2, 8, 3, 0, 8, 9, 4, 7, 8, 3, 7, 4, 4, 5, 5, 7, 6, 9, 5, 5, 7, 5, 7, 3, 3, 7, 9, 4, 1, 5, 3, 4, 8, 7, 9, 3, 5, 9, 2, 3, 6, 5, 7, 8, 2, 5, 8, 8, 9, 6, 3, 8, 0, 4, 5, 4, 0, 4, 8, 6, 2, 1, 2, 1, 3, 3, 3, 9, 6, 2, 5, 6
Offset: 0

Views

Author

Keywords

Comments

This constant is transcendental (Mahler, 1929). - Amiram Eldar, Nov 14 2020

Examples

			0.412454033640107597783361368258455283089...
In hexadecimal, .6996966996696996... .
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 6.8 Prouhet-Thue-Morse Constant, p. 437.

Crossrefs

Programs

  • Maple
    A014571 := proc()
        local nlim,aold,a ;
        nlim := ilog2(10^Digits) ;
        aold := add( A010060(n)/2^n,n=0..nlim) ;
        a := 0.0 ;
        while abs(a-aold) > abs(a)/10^(Digits-3) do
            aold := a;
            nlim := nlim+200 ;
            a := add( A010060(n)/2^n,n=0..nlim) ;
        od:
        evalf(%/2) ;
    end:
    A014571() ; # R. J. Mathar, Mar 03 2008
  • Mathematica
    digits = 105; t[0] = 0; t[n_?EvenQ] := t[n] = t[n/2]; t[n_?OddQ] := t[n] = 1-t[(n-1)/2]; FromDigits[{t /@ Range[digits*Log[10]/Log[2] // Ceiling], -1}, 2] // RealDigits[#, 10, digits]& // First (* Jean-François Alcover, Feb 20 2014 *)
    1/2-1/4*Product[1-2^(-2^k), {k, 0, Infinity}] // N[#, 105]& // RealDigits // First (* Jean-François Alcover, May 15 2014, after Steven Finch *)
    (* ThueMorse function needs $Version >= 10.2 *)
    P = FromDigits[{ThueMorse /@ Range[0, 400], 0}, 2];
    RealDigits[P, 10, 105][[1]] (* Jean-François Alcover, Jan 30 2020 *)
  • PARI
    default(realprecision, 20080); x=0.0; m=67000; for (n=1, m-1, x=x+x; x=x+sum(k=0, length(binary(n))-1, bittest(n, k))%2); x=10*x/2^m; for (n=0, 20000, d=floor(x); x=(x-d)*10; write("b014571.txt", n, " ", d)); \\ Harry J. Smith, Apr 25 2009
    
  • PARI
    1/2-prodinf(n=0,1-1.>>2^n)/4 \\ Charles R Greathouse IV, Jul 31 2012

Formula

Equals Sum_{k>=0} A010060(n)*2^(-(k+1)). [Corrected by Jianing Song, Oct 27 2018]
Equals Sum_{k>=1} 2^(-(A000069(k)+1)). - Jianing Song, Oct 27 2018
From Amiram Eldar, Nov 14 2020: (Start)
Equals 1/2 - (1/4) * A215016.
Equals 1/(3 - 1/A247950). (End)

Extensions

Corrected and extended by R. J. Mathar, Mar 03 2008

A247950 Decimal expansion of the value of a nonregular continued fraction giving tau/(3*tau-1), where tau is the Prouhet-Thue-Morse constant.

Original entry on oeis.org

1, 7, 3, 7, 6, 5, 7, 4, 9, 4, 7, 7, 6, 5, 5, 3, 6, 2, 1, 2, 6, 0, 0, 6, 7, 8, 8, 8, 5, 1, 7, 4, 6, 2, 0, 9, 9, 7, 9, 4, 3, 8, 5, 6, 2, 4, 1, 0, 6, 5, 3, 8, 3, 2, 9, 6, 2, 6, 0, 3, 6, 7, 4, 2, 8, 7, 2, 9, 8, 9, 7, 6, 6, 5, 3, 5, 8, 6, 7, 3, 9, 2, 5, 1, 4, 6, 2, 8, 7, 4, 5, 9, 6, 2, 0, 0, 2, 5, 6, 8, 3, 9, 6
Offset: 1

Views

Author

Jean-François Alcover, Oct 01 2014

Keywords

Examples

			1.737657494776553621260067888517462099794385624106538329626...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 6.8 Prouhet-Thue-Morse Constant, p. 437.

Crossrefs

Programs

  • Maple
    evalf(1/(3-1/(1/2-(1/4)*(product(1-1/2^(2^k), k=0..11)))), 120); # Vaclav Kotesovec, Oct 01 2014
  • Mathematica
    (* 10 terms suffice to get 103 correct digits *) t = Fold[Function[2^2^#2 - (2^2^#2 - 1)/#1], 2, Reverse[Range[0, 10]]]; RealDigits[t, 10, 103] // First

Formula

2 - 1/(4 - 3/(16 - 15/(256 - 255/65536 - ...))).
Pattern is generated by 2^(2^n) and 2^(2^n)-1.
Showing 1-2 of 2 results.