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.

A276383 Complement of A158919: complementary Beatty sequence to the Beatty sequence defined by the tribonacci constant tau = A058265.

Original entry on oeis.org

2, 4, 6, 8, 10, 13, 15, 17, 19, 21, 24, 26, 28, 30, 32, 35, 37, 39, 41, 43, 46, 48, 50, 52, 54, 56, 59, 61, 63, 65, 67, 70, 72, 74, 76, 78, 81, 83, 85, 87, 89, 92, 94, 96, 98, 100, 102, 105, 107, 109, 111, 113, 116, 118, 120, 122, 124, 127, 129, 131, 133, 135, 138, 140, 142, 144, 146, 149, 151, 153, 155, 157, 159, 162, 164, 166, 168, 170, 173, 175, 177, 179, 181, 184, 186, 188, 190, 192, 195, 197, 199, 201, 203, 205, 208, 210, 212, 214, 216, 219, 221, 223, 225, 227, 230, 232, 234, 236, 238, 241, 243
Offset: 1

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Author

N. J. A. Sloane, Sep 02 2016

Keywords

Comments

This is the Beatty sequence for tau_prime = 2.191487883953118747061354268227517294...,
defined by 1/tau + 1/tau_prime = 1.
Differs from A172278 at n = 162, 209, 256, 303, 324, ...
Note that Beatty sequences do not normally include 0 - see the classic pair A000201, A001950. - N. J. A. Sloane, Oct 19 2018
Note that the tribonacci numbers T = A000073 related to the ternary sequence A080843 lead to the three complementary sequences for the nonnegative integers AT(n) = A278040(n), BT(n) = A278039(n) and CT(n) = A278041(n). - Wolfdieter Lang, Sep 08 2018

Examples

			Comments from _Wolfdieter Lang_, Sep 08 2018 (Start):
The complementary sequences A158919 and A276383 begin:
n:       1 2 3 4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 ...
A158919: 1 3 5 7  9 11 12 14 16 18 20 22 23 25 27 29 31 33 34 36 ...
A276383: 2 4 6 8 10 13 15 17 19 21 24 26 28 30 32 35 37 39 41 43 ...
--------------------------------------------------------------------
The complementary sequences AT, BT and CT begin:
n:  0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15  16  17  18  19 ...
AT: 1  5  8 12 14 18 21 25 29 32 36 38 42 45 49 52  56  58  62  65 ...
BT: 0  2  4  6  7  9 11 13 15 17 19 20 22 24 26 28  30  31  33  35 ...
CT: 3 10 16 23 27 34 40 47 54 60 67 71 78 84 91 97 104 108 115 121 ...
(End)
		

Crossrefs

Similar to but strictly different from A172278.

Programs

  • Maple
    A276383 := proc(n)
        Tau := (1/3)*(1+(19+3*sqrt(33))^(1/3)+(19-3*sqrt(33))^(1/3));
        taupr := 1/(1-1/Tau) ;
        floor(n*taupr) ;
    end proc: # R. J. Mathar, Sep 04 2016
    a:=proc(n) local s,t; t:=evalf(solve(x^3-x^2-x-1=0,x),120)[1]; s:=t/(t-1); floor(n*s) end; seq(a(n),n=0..70); # Muniru A Asiru, Oct 16 2018

Formula

a(n) = floor(n*tau_prime), with tau_prime = tau/(tau - 1), where tau is the tribonacci constant A058265.
tau_prime = (1 + (19 + 3*sqrt(33))^(1/3) + (19 - 3*sqrt(33))^(1/3)) / (-2 + (19 + 3*sqrt(33))^(1/3) + (19 - 3*sqrt(33))^(1/3)). - Wolfdieter Lang, Sep 08 2018

Extensions

Edited by N. J. A. Sloane, Oct 19 2018 at the suggestion of Georg Fischer

A317202 Decimal expansion of 3 + (t^2+t^4)/2, where t = 0.543689... (A192918) is the real root of x^3 + x^2 + x = 1.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Aug 05 2018

Keywords

Comments

The minimal polynomial of this constant is 2*x^3 - 12*x^2 + 22*x - 13, and it is its unique real root. - Amiram Eldar, May 30 2023

Examples

			3.191487883953118747061354268227517293474691...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[x /. FindRoot[2*x^3 - 12*x^2 + 22*x - 13, {x, 3}, WorkingPrecision -> 120]][[1]] (* Amiram Eldar, May 30 2023 *)

A357463 Decimal expansion of the real root of 2*x^3 + 2*x - 1.

Original entry on oeis.org

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

Views

Author

Wolfdieter Lang, Sep 29 2022

Keywords

Comments

The other (complex) roots are w1*((1 + (1/9)*sqrt(129))/4)^(1/3) + ((1 - (1/9)*sqrt(129))/4)^(1/3) = -0.2119268995... + 1.0652413023...*i, and its complex conjugate, where w1 = (-1 + sqrt(3))/2 = exp((2/3)*Pi*i).
Using hyperbolic functions these roots are -(1/3)*sqrt(3)*(sinh((1/3)*arcsinh((3/4)*sqrt(3))) - sqrt(3)*cosh((1/3)*arcsinh((3/4)*sqrt(3)))*i), and its complex conjugate.

Examples

			0.423853799069783271378040062625515233676388197185177540823008396819954728...
		

Crossrefs

Cf. A316711 (Comment).

Programs

  • Mathematica
    RealDigits[x /. FindRoot[2*x^3 + 2*x - 1, {x, 1}, WorkingPrecision -> 100]][[1]] (* Amiram Eldar, Sep 29 2022 *)

Formula

r = ((1 +(1/9)*sqrt(129))/4)^(1/3) - (1/3)*((1 + (1/9)*sqrt(129))/4)^(-1/3).
r = ((1 + (1/9)*sqrt(129))/4)^(1/3) + w1*((1 - (1/9)*sqrt(129))/4)^(1/3), where w1 = (-1 + sqrt(3))/2, one of the complex roots of x^3 - 1.
r = (2/3)*sqrt(3)*sinh((1/3)*arcsinh((3/4)*sqrt(3))).
Showing 1-3 of 3 results.