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.

A081750 Simple continued fraction of 2*e.

Original entry on oeis.org

5, 2, 3, 2, 3, 1, 2, 1, 3, 4, 3, 1, 4, 1, 3, 6, 3, 1, 6, 1, 3, 8, 3, 1, 8, 1, 3, 10, 3, 1, 10, 1, 3, 12, 3, 1, 12, 1, 3, 14, 3, 1, 14, 1, 3, 16, 3, 1, 16, 1, 3, 18, 3, 1, 18, 1, 3, 20, 3, 1, 20, 1, 3, 22, 3, 1, 22, 1, 3, 24, 3, 1, 24, 1, 3, 26, 3, 1, 26, 1, 3, 28, 3, 1, 28, 1, 3, 30, 3, 1, 30, 1, 3, 32
Offset: 1

Views

Author

Benoit Cloitre, Apr 08 2003

Keywords

Comments

Decimal expansion is A019762. - Michael Somos, May 07 2012

Examples

			2*e = 5 + 1 / (2 + 1 / (3 + 1 / (2 + 1 / (3 + 1 / (1 + ...))))). - _Michael Somos_, May 07 2012
		

Crossrefs

Programs

  • Mathematica
    ContinuedFraction[ 2E, 94] (* Robert G. Wilson v, May 07 2012 *)
  • PARI
    A081750(n) = if(1==n,5,if(n<6,2+(n%2), my(k=n\6, r=n%6); if(0==r || 2==r, 1, if(1==r, 2*k, if(n%2, 3, 2*(k+1)))))); \\ Antti Karttunen, Feb 20 2023

Formula

First 5 terms are 5, 2, 3, 2, 3.
For k >= 1, a(6k)=1; a(6k+1)=2k; a(6k+2)=1; a(6k+3)=3; a(6k+4)=2k+2; a(6k+5)=3.