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 1-2 of 2 results.

A190258 Decimal expansion of (x + sqrt(2 + 4x))/2, where x=sqrt(2).

Original entry on oeis.org

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

Views

Author

Clark Kimberling, May 06 2011

Keywords

Comments

The rectangle R whose shape (i.e., length/width) is (x+sqrt(2+4x))/2, where x=sqrt(2), can be partitioned into rectangles of shapes sqrt(2) and 1 in a manner that matches the periodic continued fraction [x, 1, x, 1, ...]. R can also be partitioned into squares so as to match the nonperiodic continued fraction [2,11,32,1,4,10,2,1,...] at A190259. For details, see A188635.

Examples

			2.090657850852244775710089635005221328095...
		

Crossrefs

Programs

  • Magma
    [(Sqrt(2) + Sqrt(2+4*Sqrt(2)))/2]; // G. C. Greubel, Dec 26 2017
  • Mathematica
    r=2^(1/2);
    FromContinuedFraction[{r,1, {r,1}}]
    FullSimplify[%]
    ContinuedFraction[%, 100]  (* A190258 *)
    RealDigits[N[%%, 120]]     (* A190259 *)
    N[%%%, 40]
    RealDigits[(Sqrt[2]+Sqrt[2+4Sqrt[2]])/2,10,120][[1]] (* Harvey P. Dale, Jun 20 2021 *)
  • PARI
    sqrt(1/2)+sqrt(1/2+sqrt(2))
    

A190261 Continued fraction of (1 + sqrt(1 + 2x))/2, where x=sqrt(2).

Original entry on oeis.org

1, 2, 11, 32, 1, 4, 10, 2, 1, 1, 3, 1, 1, 5, 2, 3, 2, 1, 4, 2, 3, 2, 41, 1, 2, 1, 1, 3, 4, 1, 35, 1, 5, 1, 29661, 2, 1, 1, 2, 1, 1, 1, 1, 1, 2, 5, 2, 2, 2, 1, 1, 1, 5, 15, 2, 1, 1, 1, 2, 7, 1, 1, 1, 13, 1, 1, 1, 1, 20, 2, 1, 2, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 3, 14, 1, 8, 2, 1, 1, 1, 1, 2, 1, 3, 2, 3, 1, 8, 2
Offset: 1

Views

Author

Clark Kimberling, May 06 2011

Keywords

Comments

1 followed by A190259.

Crossrefs

Programs

  • Magma
    ContinuedFraction((1+Sqrt(1+2*Sqrt(2)))/2) // G. C. Greubel, Dec 26 2017
  • Mathematica
    r=2^(1/2);
    FromContinuedFraction[{1, r, {1, r}}]
    FullSimplify[%]
    ContinuedFraction[%, 100]  (* A190261 *)
    RealDigits[N[%%, 120]]     (* A190260 *)
    N[%%%, 40]
    ContinuedFraction[(1+Sqrt[1+2Sqrt[2]])/2,100] (* Harvey P. Dale, Jan 27 2013 *)
  • PARI
    contfrac((1+sqrt(1+2*sqrt(2)))/2) \\ G. C. Greubel, Dec 26 2017
    
Showing 1-2 of 2 results.