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.

A048649 Decimal expansion of Sum_{m>=0} 1/(2^2^m - 1).

Original entry on oeis.org

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

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Examples

			1.40393682788217832057620607413720935453...
		

Crossrefs

Programs

  • Mathematica
    NSum[1/(2^2^m - 1), {m, 0, Infinity}, WorkingPrecision -> 99] // RealDigits // First (* Jean-François Alcover, Feb 12 2013 *)
  • PARI
    { default(realprecision, 20080); x=suminf(m=0, 1/(2^2^m - 1)); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b048649.txt", n, " ", d)); } \\ Harry J. Smith, May 07 2009

Formula

Equals 1 + Sum_{n>=1} A007814(n)/2^n = 4/3 + Sum_{n>=1} A007814(n)/4^n = 7/5 + Sum_{n>=1} A007814(n)/16^n. - Amiram Eldar, Nov 06 2020

Extensions

Deleted old PARI program. - Harry J. Smith, May 20 2009