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.

A188640 Decimal expansion of e + sqrt(1+e^2).

Original entry on oeis.org

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

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Author

Clark Kimberling, Apr 10 2011

Keywords

Comments

The shape of a rectangle WXYZ, denoted by [WXYZ], is defined by length/width: [WXYZ]=max{|WX|/|YZ|, |YZ|/|WX|}. Consider the following configuration of rectangles AEFD, EBCF, ABCD, where AEFD is not a square:
D................F....C
.......................
.......................
.......................
A................E....B
Let r=[AEFD]. The r-extension rectangle of AEFD is here introduced as the rectangle ABCD for which [AEFD]=[EBCF] and |AE|<>|EB|. That is, AEFD has the prescribed shape r, and AEFD and EBCF are similar without being congruent.
We extend the definition of r-extension rectangle to the case that 0
Then for all r>0, it is easy to prove that [ABCD] = (r+sqrt(4+r^2))/2.
This here is the length/width ratio for the (2e)-extension rectangle.
A (2e)-extension rectangle matches the continued fraction A188796 for the shape L/W=(e+sqrt(1+e^2). This is analogous to the matching of a golden rectangle to the continued fraction [1,1,1,1,1,1,1,...]. Specifically, for the (2e)-extension rectangle, 5 squares are removed first, then 1 square, then 1 square, then 1 square, then 1 square, then 2 squares..., so that the original rectangle is partitioned into an infinite collection of squares.
Shapes of other r-extension rectangles, partitionable into a collection of squares in accord with the continued fraction of the shape [ABCD], are approximated at A188635-A188639, A188655-A188659, and A188720-A188737.
For (related) r-contraction rectangles, see A188738 and A188739.

Examples

			Length/width = 5.61466856004905343925478283318633736023982...
		

Programs

  • Magma
    SetDefaultRealField(RealField(100)); Exp(1) + Sqrt(1 + Exp(2)); // G. C. Greubel, Oct 31 2018
  • Maple
    evalf(exp(1)+sqrt(1+exp(2)),140); # Muniru A Asiru, Nov 01 2018
  • Mathematica
    r=2E; t=(r+(4+r^2)^(1/2))/2; FullSimplify[t]
    N[t, 130]
    RealDigits[N[t, 130]][[1]]
  • PARI
    exp(1)+sqrt(1+exp(2)) \\ Charles R Greathouse IV, Jun 16 2011
    

Formula

Equals exp(A366599). - Amiram Eldar, Oct 18 2023

A188722 Decimal expansion of (Pi+sqrt(4+Pi^2))/2.

Original entry on oeis.org

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

Author

Clark Kimberling, Apr 09 2011

Keywords

Comments

Decimal expansion of shape of a Pi-extension rectangle; see A188640 for definitions of shape and r-extension rectangle. Briefly, an r-extension rectangle is composed of two rectangles having shape r.
A Pi-extension rectangle matches the continued fraction A188723 of the shape L/W = (Pi+sqrt(4+Pi^2))/2. This is analogous to the matching of a golden rectangle to the continued fraction [1,1,1,1,1,1,1,...]. Specifically, for a Pi-extension rectangle, 3 squares are removed first, then 2 squares, then 3 squares, then 4 squares, then 2 squares,..., so that the original rectangle is partitioned into an infinite collection of squares.

Examples

			3.4328922159134832442014603702358109669027341058202444195...
		

Crossrefs

Programs

  • Mathematica
    r = Pi; t = (r + (4 + r^2)^(1/2))/2; FullSimplify[t]
    N[t, 130]
    RealDigits[N[t, 130]][[1]]
    ContinuedFraction[t, 120]
  • PARI
    (Pi+sqrt(4+Pi^2))/2 \\ Michel Marcus, Apr 01 2015

Formula

(Pi+sqrt(4+Pi^2))/2 = [Pi,Pi,Pi,...] (continued fraction). - Clark Kimberling, Sep 23 2013

A188721 Continued fraction of (e+sqrt(4+e^2))/2.

Original entry on oeis.org

3, 21, 2, 40, 1, 8, 1, 18, 1, 4, 2, 7, 14, 25, 1, 2, 1, 4, 1, 1, 1, 1, 2, 8, 50, 4, 1, 1, 3, 1, 11, 1, 1, 2, 3, 1, 1, 3, 1, 2, 22, 1, 1, 4, 1, 4, 1, 1, 4, 4, 2, 2, 2, 57, 1, 1, 34, 5, 1, 2, 2, 1, 1, 8, 13, 2, 3, 3, 17, 1, 1, 49, 1, 2, 1, 5, 1, 7, 1, 9, 1, 11, 1, 1, 7, 13, 1, 1, 59, 4, 8, 1, 3, 1, 4, 6, 1, 9, 11, 1, 1, 4, 456, 2, 8, 23, 2, 4, 2, 2, 1066, 1, 2, 2, 1, 11, 1, 3, 2, 26
Offset: 0

Author

Clark Kimberling, Apr 09 2011

Keywords

Comments

See A188640 and A188720.

Crossrefs

Cf. A188640, A188720 (decimal expansion).

Programs

  • Mathematica
    r = E; t = (r + (4 + r^2)^(1/2))/2; FullSimplify[t]
    N[t, 130]
    RealDigits[N[t, 130]][[1]]
    ContinuedFraction[t, 120]

Extensions

Offset changed by Andrew Howroyd, Jul 07 2024
Showing 1-3 of 3 results.