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.

A100924 Digits in the decimal expansion of A100923 interpreted as digits of a binary number 0.1110101001010...

Original entry on oeis.org

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

Views

Author

Joseph Biberstine (jrbibers(AT)indiana.edu), Nov 22 2004

Keywords

Examples

			0.91529479751356057973361539728562081112510204536957775...

Crossrefs

Cf. A100923, A100925.

Programs

  • Mathematica
    N[Sum[If[And[PrimeQ[6*k - 1], PrimeQ[6*k + 1]], 1, 0]*2^(-k), {k, 1, 500}], 110]

A100925 Continued fraction expansion of constant defined in A100924.

Original entry on oeis.org

0, 1, 10, 1, 4, 6, 1, 7, 3, 1, 1, 5, 18, 7, 1, 3, 2, 133, 5, 1, 5, 4, 1, 4, 1, 11, 19, 1, 4, 4, 1, 7, 1, 23, 1, 4, 2, 4, 1, 13, 1, 1, 2, 17, 1, 4, 2, 1, 1, 5, 9, 3, 2, 207, 4, 1, 3, 4, 4, 31, 2, 28, 2, 2, 1, 1, 7, 3, 3, 3, 1, 1, 792, 9, 1, 7, 3, 2, 2, 5, 2, 4, 1, 1, 1, 64, 2, 1, 2, 4, 1, 4, 73, 2, 1, 1, 1
Offset: 0

Views

Author

Joseph Biberstine (jrbibers(AT)indiana.edu), Nov 22 2004

Keywords

Examples

			0.9152947975135605797336153972856208111251020453695777508300794...

Crossrefs

Cf. A100923, A100924 (decimal expansion).

Programs

  • Mathematica
    ContinuedFraction[Sum[If[And[PrimeQ[6*k - 1], PrimeQ[6*k + 1]], 1, 0]*2^(-k), {k, 1, 500}], 110]

Extensions

Offset changed by Andrew Howroyd, Aug 04 2024

A161996 A (negated) characteristic function of twin composite odd numbers.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1
Offset: 1

Views

Author

Pierre CAMI, Jun 24 2009

Keywords

Comments

a(n) = 0 if n is a member of A060461, otherwise a(n) = 1.

Links

Crossrefs

Cf. A060461, A100923.

Programs

  • Mathematica
    If[AllTrue[6#+{1,-1},CompositeQ],0,1]&/@Range[300] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 15 2015 *)
  • PARI
    A161996(n) = (isprime((6*n)-1)||isprime((6*n)+1)); \\ Antti Karttunen, Dec 15 2017

Extensions

Definition rephrased by R. J. Mathar, Aug 14 2009
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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