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 1-3 of 3 results.

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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Author

Keywords

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

A048638 Height of lattice of parameters of mixed orthogonal arrays with 2^n runs and strength 2.

Original entry on oeis.org

1, 4, 9, 21, 42, 86, 171, 358, 715, 1431
Offset: 0

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Author

N. J. A. Sloane, E. M. Rains, J. Stufken

Keywords

Crossrefs

A048650 Continued fraction for Sum_{m>=0} 1/(2^2^m - 1).

Original entry on oeis.org

1, 2, 2, 9, 1, 3, 5, 1, 2, 1, 1, 1, 1, 8, 2, 1, 1, 2, 1, 12, 19, 24, 1, 18, 12, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 8, 1, 1, 5, 2, 5, 8, 1, 4, 2, 5, 1, 1, 8, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 12, 18, 1, 7, 2, 1, 1, 2, 4, 1, 5, 4, 2, 1, 1, 1, 1, 1, 4, 64, 14, 1, 6, 3, 1, 6
Offset: 0

Views

Author

Keywords

Examples

			1.40393682788217832057620607413720935453...
1.403936827882178320576206074... = 1 + 1/(2 + 1/(2 + 1/(9 + 1/(1 + ...)))). - _Harry J. Smith_, May 03 2009
		

Crossrefs

Cf. A048164, A048649 (decimal expansion).

Programs

  • PARI
    { allocatemem(932245000); default(realprecision, 21000); x=suminf(m=0, 1/(2^2^m - 1)); x=contfrac(x); for (n=1, 20000, write("b048650.txt", n-1, " ", x[n])); } \\ Harry J. Smith, May 07 2009

Extensions

Deleted old PARI program. - Harry J. Smith, May 20 2009
Offset changed by Andrew Howroyd, Aug 03 2024
Showing 1-3 of 3 results.