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 1-10 of 107 results. Next

A158919 Beatty sequence for the tribonacci constant tau (A058265): a(n) = floor(n*tau).

Original entry on oeis.org

0, 1, 3, 5, 7, 9, 11, 12, 14, 16, 18, 20, 22, 23, 25, 27, 29, 31, 33, 34, 36, 38, 40, 42, 44, 45, 47, 49, 51, 53, 55, 57, 58, 60, 62, 64, 66, 68, 69, 71, 73, 75, 77, 79, 80, 82, 84, 86, 88, 90, 91, 93, 95, 97, 99, 101, 103, 104, 106, 108, 110
Offset: 0

Views

Author

Eric Culver (weux082690(AT)yahoo.com), Mar 30 2009

Keywords

Comments

Also called the spectrum of tau. Note that A276384 agrees with this sequence for n <= 17160 but disagrees beyond that point. In fact a(17161) = 31564, whereas A276384(17161) = 31563. - N. J. A. Sloane, Sep 03 2016

Examples

			a(3) = floor(3*q) = floor(3*1.8392867...) = floor(5.51786...) = 5.
		

Crossrefs

Cf. A058265, A140099 (spectrum of 1+tau), A276384, A277722, A277723.

Programs

  • Magma
    [Floor(n * (1/3 + 1/3 * (19 - 3 * Sqrt(33))^(1/3) + 1/3 * (19 + 3 * Sqrt(33))^(1/3))) : n in [0..80]]; // Vincenzo Librandi, Oct 28 2018
  • Maple
    x := (1/3)*(1+(19+3*sqrt(33))^(1/3)+(19-3*sqrt(33))^(1/3)) ;
    [seq(floor(n*x),n=0..200)]; # R. J. Mathar, Sep 11 2011
  • Mathematica
    a[n_] := Floor[n Root[#^3 - #^2 - # - 1&, 1]];
    Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Oct 28 2018 *)

Formula

a(n) = floor(n*A058265).

A276800 Decimal expansion of t^2, where t is the tribonacci constant A058265.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Oct 28 2016

Keywords

Comments

The minimal polynomial of this constant is x^3 - 3*x^2 - x - 1, and it is its unique real root. - Amiram Eldar, May 27 2023

Examples

			3.38297576790623749412270853645503458694938204374857618201956267723537...
		

Crossrefs

Programs

  • Mathematica
    A276800L[n_] := RealDigits[(1/3 (1 + (19 - 3 Sqrt[33])^(1/3) + (19 + 3 Sqrt[33])^(1/3)))^2, 10, n][[1]]; A276800L[107] (* JungHwan Min, Nov 06 2016 *)
    RealDigits[x /. FindRoot[x^3 - 3*x^2 - x - 1, {x, 3}, WorkingPrecision -> 120]][[1]] (* Amiram Eldar, May 27 2023 *)
  • PARI
    polrootsreal(x^3-3*x^2-x-1)[1] \\ Charles R Greathouse IV, Aug 21 2023

A140099 A Beatty sequence: a(n) = [n*(1+t)], where t = tribonacci constant (A058265); complement of A140098.

Original entry on oeis.org

2, 5, 8, 11, 14, 17, 19, 22, 25, 28, 31, 34, 36, 39, 42, 45, 48, 51, 53, 56, 59, 62, 65, 68, 70, 73, 76, 79, 82, 85, 88, 90, 93, 96, 99, 102, 105, 107, 110, 113, 116, 119, 122, 124, 127, 130, 133, 136, 139, 141, 144, 147, 150, 153, 156, 159, 161, 164, 167, 170, 173
Offset: 1

Views

Author

Paul D. Hanna, Jun 01 2008

Keywords

Comments

Note that A276385 agrees with this sequence for n <= 17160 but disagrees beyond that point. In fact a(17161) = 48725, whereas A276385(17161) = 48724. - N. J. A. Sloane, Sep 03 2016
Also somewhat similar to but different from A109232. - N. J. A. Sloane, Sep 04 2016

Examples

			Tribonacci constant: t = 1.839286755214161132551852564653286600...
		

Crossrefs

Cf. A140098 (complement), A140101, A058265, A109232, A276385.
See also A158919 (Beatty sequence for tribonacci constant tau), A275926 (deviation from A140101).

Programs

  • Mathematica
    With[{tc=1/3 (1+Surd[19-3Sqrt[33],3])+1/3 Surd[19+3Sqrt[33],3]},Array[ Floor[ (1+tc)*#]&,70]] (* Harvey P. Dale, Dec 05 2013 *)
  • PARI
    {a(n)=local(t=(1+(19+3*sqrt(33))^(1/3)+(19-3*sqrt(33))^(1/3))/3);floor(n*(1+t))}

Formula

For n >= 1, a(n) = A158919(n)+n. - N. J. A. Sloane, Sep 04 2016

A276801 Decimal expansion of t^3, where t is the tribonacci constant A058265.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Oct 28 2016

Keywords

Comments

A cubic integer with minimal polynomial x^3 - 7x^2 + 5x - 1, of which it is the unique real root. - Charles R Greathouse IV, Nov 06 2016

Examples

			6.222262523120398626674561101108321187373560789846168428798321316639575...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[x /. FindRoot[x^3 - 7*x^2 + 5*x - 1, {x, 6}, WorkingPrecision -> 120]][[1]] (* Amiram Eldar, May 27 2023 *)
  • PARI
    polrootsreal(x^3-7*x^2+5*x-1)[1] \\ Charles R Greathouse IV, Nov 06 2016

Formula

1/t + 1/t^2 + 1/t^3 = 1/A058265 + 1/A276800 + 1/A276801 = 1.
From Dimitri Papadopoulos, Nov 07 2023: (Start)
t^3 = (A276800^2 + 1)/2.
t^3 + 1/t^3 = t + 1/t + 4.
t^3 = (1/4)*(t + 1)^2*(t - 1)^2*(t^2 + 1). (End)

A277722 a(n) = floor(n*tau^2) where tau is the tribonacci constant (A058265).

Original entry on oeis.org

0, 3, 6, 10, 13, 16, 20, 23, 27, 30, 33, 37, 40, 43, 47, 50, 54, 57, 60, 64, 67, 71, 74, 77, 81, 84, 87, 91, 94, 98, 101, 104, 108, 111, 115, 118, 121, 125, 128, 131, 135, 138, 142, 145, 148, 152, 155, 158, 162, 165, 169, 172, 175, 179, 182, 186, 189, 192, 196, 199, 202, 206, 209, 213, 216, 219
Offset: 0

Views

Author

N. J. A. Sloane, Oct 30 2016

Keywords

Crossrefs

Programs

  • Maple
    A277722 := proc(n)
        a276800 :=  3.3829757679062374941227085364550345869493820437485761820195626772353718960099402922235933340043661396041006 ;
        floor(n*a276800) ;
    end proc:
    seq(A277722(n),n=0..100) ; # R. J. Mathar, Nov 02 2016
  • Mathematica
    A277722[n_] := Floor[n (1/3 (1 + (19 - 3 Sqrt[33])^(1/3) + (19 + 3 Sqrt[33])^(1/3)))^2]; Array[A277722, 66, 0] (* JungHwan Min, Nov 06 2016 *)

A276799 a(n) = floor(n*t^2) - A003145(n), where t = 1.8392867... is the tribonacci constant A058265.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 2, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 2, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1
Offset: 1

Views

Author

N. J. A. Sloane, Oct 28 2016

Keywords

Comments

a(n) is in {-1, 0, 1, 2}, but the first n for which -1 appears is n = 329. - Jeffrey Shallit, Nov 19 2016

Crossrefs

Cf. A003144, A003145, A003146, A275926, A058265, A276800, A277721, A278352 (positions of -1's).

Formula

a(n) = A277722(n) - A003145(n). - R. J. Mathar, Nov 02 2016

A277723 a(n) = floor(n*tau^3) where tau is the tribonacci constant (A058265).

Original entry on oeis.org

0, 6, 12, 18, 24, 31, 37, 43, 49, 56, 62, 68, 74, 80, 87, 93, 99, 105, 112, 118, 124, 130, 136, 143, 149, 155, 161, 168, 174, 180, 186, 192, 199, 205, 211, 217, 224, 230, 236, 242, 248, 255, 261, 267, 273, 280, 286, 292, 298, 304, 311, 317, 323, 329, 336, 342, 348, 354, 360, 367, 373, 379, 385
Offset: 0

Views

Author

N. J. A. Sloane, Oct 30 2016

Keywords

Crossrefs

Programs

Formula

By definition, a(n) = n*tau^3 + O(1). - Charles R Greathouse IV, Nov 06 2016

A140098 A Beatty sequence: a(n) = [n*(1+1/t)], where t = tribonacci constant (A058265); complement of A140099.

Original entry on oeis.org

1, 3, 4, 6, 7, 9, 10, 12, 13, 15, 16, 18, 20, 21, 23, 24, 26, 27, 29, 30, 32, 33, 35, 37, 38, 40, 41, 43, 44, 46, 47, 49, 50, 52, 54, 55, 57, 58, 60, 61, 63, 64, 66, 67, 69, 71, 72, 74, 75, 77, 78, 80, 81, 83, 84, 86, 87, 89, 91, 92, 94, 95, 97, 98, 100, 101, 103, 104, 106
Offset: 1

Views

Author

Paul D. Hanna, Jun 01 2008

Keywords

Examples

			Tribonacci constant: t = 1.839286755214161132551852564653286600...
1 + 1/t = 1.54368901269207636157085597180174798652520...
		

Crossrefs

Programs

  • Mathematica
    Floor[Range[100]*(1 + 1/Root[#^3-#^2-#-1 &, 1])] (* Paolo Xausa, Jul 09 2024 *)
  • PARI
    {a(n)=local(t=(1+(19+3*sqrt(33))^(1/3)+(19-3*sqrt(33))^(1/3))/3);floor(n*(1+1/t))}

A239502 (Round(q^prime(n)) - 1)/prime(n), where q is the tribonacci constant (A058265).

Original entry on oeis.org

4, 10, 74, 212, 1856, 5618, 53114, 1630932, 5161442, 167427844, 1729192432, 5577731626, 58401766802, 2005139696964, 69737304018266, 228184540445268, 8043367476888770, 86866463049858250, 285815985033409648, 10225367934387562098, 111384745483589787826
Offset: 3

Views

Author

Keywords

Comments

For n>=3, round(q^prime(n)) == 1 (mod 2*prime(n)). Proof in Shevelev link. In particular, all terms are even.

Examples

			For n=3, q^5 = 21.049..., so a(3) = (21 - 1)/5 = 4.
		

Crossrefs

A019712 Continued fraction expansion of tribonacci constant A058265.

Original entry on oeis.org

1, 1, 5, 4, 2, 305, 1, 8, 2, 1, 4, 6, 14, 3, 1, 13, 5, 1, 7, 23, 1, 16, 4, 1, 1, 1, 1, 1, 2, 17, 1, 3, 1, 1, 1, 29, 1, 6, 1, 3, 1, 1, 1, 1, 3, 2, 5, 1, 63, 2, 1, 2, 5, 1, 4, 11, 2, 2, 1, 1, 1, 1, 1, 2, 1, 9, 3, 3, 18, 1, 38, 2, 4, 1, 20, 3, 1, 1, 1, 5, 2, 2, 1, 1, 1, 44, 6, 3, 9, 1, 1, 1, 1, 3, 3, 1, 6
Offset: 0

Views

Author

Robert G. Wilson v, Dec 07 2000

Keywords

Comments

The only real root of the equation x^3 - x^2 - x - 1 = 0.

Examples

			1.839286755214161132551852564... = 1 + 1/(1 + 1/(5 + 1/(4 + 1/(2 + ...)))). - _Harry J. Smith_, May 30 2009
		

References

  • David Wells, "The Penguin Dictionary of Curious and Interesting Numbers," Revised Edition, Penguin Books, London, England, 1997, page 23.

Crossrefs

Cf. A058265 (decimal expansion), A319428/A319429 (convergents).

Programs

  • Mathematica
    ContinuedFraction[ 1/3 + 1/3*(19 - 3*Sqrt[33])^(1/3) + 1/3*(19 + 3*Sqrt[33])^(1/3), 100]
  • PARI
    { allocatemem(932245000); default(realprecision, 21000); x=contfrac(solve(x=1, 2, x^3 - x^2 - x - 1)); for (n=0, 20000, write("b019712.txt", n, " ", x[n+1])); } \\ Harry J. Smith, May 30 2009
Showing 1-10 of 107 results. Next