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.

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A158468 Decimal expansion of hz = limit_{k -> infinity} 1 + k - Sum_{j = -k..k} exp(-2^j).

Original entry on oeis.org

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

Views

Author

Alois P. Heinz, Mar 19 2009

Keywords

Comments

Curiously, this constant is close to gamma/log(2)+1/2 = 1.332746177... - Jean-François Alcover, Mar 24 2014

Examples

			1.3327473824328992250086010983738997044167439822598445365797...
		

Crossrefs

Cf. A100668 (gamma/log(2)), A158469 (continued fraction), A159835 (Engel expansion), A339168.

Programs

  • Maple
    hz:= limit(1+k -sum(exp(-2^j), j=-k..k), k=infinity):
    hzs:= convert(evalf(hz/10, 130), string):
    seq(parse(hzs[n+1]), n=1..120);
  • Mathematica
    digits = 105; Clear[f]; f[k_] := f[k] = 1 + k - Sum[Exp[-2^j], {j, -k, k}] // RealDigits[#, 10, digits+1]& // First // Quiet; f[1]; f[n=2]; While[f[n] != f[n-1], n++] ; f[n] // Most (* Jean-François Alcover, Feb 19 2013 *)

Formula

Equals gamma/log(2)+1/2 + Sum_{k>=1} Im(Gamma(1-2*k*Pi*i/log(2)))/(k*Pi). - Toshitaka Suzuki, Feb 10 2017
Also equals limit_{k->oo} 1 + Sum_{j>=1} 1-(1-1/2^j)^(2^k). - Toshitaka Suzuki, Feb 12 2017

A158469 Continued fraction for hz = limit_{k -> infinity} 1 + k - Sum_{j = -k..k} exp(-2^j).

Original entry on oeis.org

1, 3, 189, 3, 2, 2, 1, 5, 4, 1, 1, 3, 1, 1, 1, 5, 8, 12, 1, 22, 7, 14, 1, 2, 1, 5, 1, 4, 222, 1, 1, 2, 3, 24, 6, 27, 1, 15, 1, 9, 1, 1, 18, 6, 24, 2, 1, 7, 1, 4, 2, 2, 1, 1, 84, 1, 1, 1, 3, 1, 1, 1, 1, 1, 5, 15, 3, 13, 3, 2, 14, 1, 1, 1, 10, 15, 10, 1, 6, 120, 1, 31, 2, 4, 2, 7, 2, 2, 1, 1, 1, 1, 1, 3, 7
Offset: 0

Views

Author

Alois P. Heinz, Mar 19 2009

Keywords

Examples

			1.33274738243289922500860109837389970441674398225984453657972 ...
		

Crossrefs

Cf. A158468 (decimal expansion), A159835 (Engel expansion).

Programs

  • Maple
    with(numtheory): hz:= limit(1+k -sum(exp(-2^j), j=-k..k), k=infinity): cfrac(evalf(hz, 130), 100, 'quotients')[];
  • Mathematica
    terms = 95; digits = terms+15; Clear[f]; f[k_] := f[k] = 1+k-Sum[Exp[-2^j], {j, -k, k}] // RealDigits[#, 10, digits+1]& // First // Quiet; f[1]; f[n = 2]; While[f[n] != f[n-1], n++]; hz = FromDigits[f[n]]*10^-digits; ContinuedFraction[hz, terms] (* Jean-François Alcover, Mar 23 2017 *)
Showing 1-2 of 2 results.