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.

A010513 Decimal expansion of square root of 60.

Original entry on oeis.org

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

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Author

Keywords

Comments

Continued fraction expansion is 7 followed by {1, 2, 1, 14} repeated. - Harry J. Smith, Jun 07 2009
With a different offset, decimal expansion of 0.6. In a unimodal distribution, the mean and median differ by at most 0.6 standard deviations (and this is sharp), see Basu & DasGupta. - Charles R Greathouse IV, Oct 01 2024

Examples

			7.745966692414833770358530799564799221665843410583181653175147532226966....
		

Crossrefs

Cf. A040052 (continued fraction).

Programs

  • Mathematica
    RealDigits[N[Sqrt[60],200]][[1]] (* Vladimir Joseph Stephan Orlovsky, Feb 25 2011 *)
  • PARI
    { default(realprecision, 20080); x=sqrt(60); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b010513.txt", n, " ", d)); } \\ Harry J. Smith, Jun 07 2009

Formula

Equals 10 * sqrt(3/5) = 10 * Sum_{k>=0} (-1)^k * binomial(2*k,k)/6^k. - Amiram Eldar, Aug 03 2020
Equals 2*A010472 = A011053^2 = 30*A020772 = 1/A020817. - Hugo Pfoertner, Oct 02 2024

A041105 Denominators of continued fraction convergents to sqrt(60).

Original entry on oeis.org

1, 1, 3, 4, 59, 63, 185, 248, 3657, 3905, 11467, 15372, 226675, 242047, 710769, 952816, 14050193, 15003009, 44056211, 59059220, 870885291, 929944511, 2730774313, 3660718824, 53980837849, 57641556673, 169263951195, 226905507868, 3345941061347, 3572846569215
Offset: 0

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Author

Keywords

Comments

Interspersion of 4 linear recurrences with constant coefficients. - Gerry Martens, Jun 10 2015

Crossrefs

Programs

  • Magma
    I:=[1, 1, 3, 4, 59, 63, 185, 248]; [n le 8 select I[n] else 62*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 11 2013
  • Maple
    numtheory:-cfrac(sqrt(60),100,'con','den'):
    den[1..-2]; # Robert Israel, Jun 09 2015
  • Mathematica
    Denominator[Convergents[Sqrt[60], 30]] (* Vincenzo Librandi, Dec 11 2013 *)
    d0 := LinearRecurrence[{62, -1}, {1, 59}, 20]
    d1 := LinearRecurrence[{62, -1}, {1, 63}, 20] (* A258684  *)
    d2 := LinearRecurrence[{62, -1}, {3, 185}, 20]
    d3 := LinearRecurrence[{62, -1}, {4, 248}, 20]
    Flatten[MapIndexed[{d0[[#]] , d1[[#]], d2[[#]] , d3[[#]]} &,
      Range[10]]] (* Gerry Martens, Jun 09 2015 *)
    LinearRecurrence[{0, 0, 0, 62, 0, 0, 0, -1},{1, 1, 3, 4, 59, 63, 185, 248},30] (* Ray Chandler, Aug 03 2015 *)

Formula

G.f.: -(x^2-x-1)*(x^4+4*x^2+1) / ((x^4-8*x^2+1)*(x^4+8*x^2+1)). - Colin Barker, Nov 12 2013
a(n) = 62*a(n-4) - a(n-8). - Vincenzo Librandi, Dec 11 2013

Extensions

More terms from Colin Barker, Nov 12 2013

A176020 Decimal expansion of (3+sqrt(15))/3.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 06 2010

Keywords

Comments

Continued fraction expansion of (3+sqrt(15))/3 is A010693.
a(n) = A020817(n-1) for n > 1; a(1) = 2.

Examples

			(3+sqrt(15))/3 = 2.29099444873580562839...
		

Crossrefs

Cf. A010472 (decimal expansion of sqrt(15)), A176016 (decimal expansion of (3+sqrt(15))/6), A010693 (repeat 2, 3), A020817 (decimal expansion of 1/sqrt(60)).

Programs

  • Mathematica
    RealDigits[(3+Sqrt[15])/3,10,120][[1]] (* Harvey P. Dale, May 20 2013 *)
Showing 1-3 of 3 results.