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 1-5 of 5 results.

A248273 Egyptian fraction representation of sqrt(47) (A010501) using a greedy function.

Original entry on oeis.org

6, 2, 3, 45, 10097, 180933939, 70214804893433857, 24596197522004292913199742834240369, 851917396155337556711167562167009352482986581505723891411145951010937, 1830843559366860042528367793031819716270540620095563249767306742965459078226069734667092696644523226923832775331940549734586475295256730688
Offset: 0

Views

Author

Robert G. Wilson v, Oct 04 2014

Keywords

Crossrefs

Egyptian fraction representations of the square roots: A006487, A224231, A248235-A248322.
Egyptian fraction representations of the cube roots: A129702, A132480-A132574.

Programs

  • Mathematica
    Egyptian[nbr_] := Block[{lst = {IntegerPart[nbr]}, cons = N[ FractionalPart[ nbr], 2^20], denom, iter = 8}, While[
    iter > 0, denom = Ceiling[ 1/cons]; AppendTo[ lst, denom]; cons -= 1/denom; iter--]; lst]; Egyptian[ Sqrt[ 47]]

A010137 Continued fraction for sqrt(47).

Original entry on oeis.org

6, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12, 1, 5, 1, 12
Offset: 0

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Author

Keywords

Examples

			6.85565460040104412493587144... = 6 + 1/(1 + 1/(5 + 1/(1 + 1/(12 + ...)))). - _Harry J. Smith_, Jun 06 2009
		

References

  • James J. Tattersall, Elementary Number Theory in Nine Chapters, Cambridge University Press, 1999, page 276.

Crossrefs

Cf. A010501 (decimal expansion).

Programs

  • Mathematica
    ContinuedFraction[Sqrt[47],300] (* Vladimir Joseph Stephan Orlovsky, Mar 07 2011 *)
  • PARI
    { allocatemem(932245000); default(realprecision, 21000); x=contfrac(sqrt(47)); for (n=0, 20000, write("b010137.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 06 2009

Formula

From Amiram Eldar, Nov 12 2023: (Start)
Multiplicative with a(2) = 5, a(2^e) = 12 for e >= 2, and a(p^e) = 1 for an odd prime p.
Dirichlet g.f.: zeta(s) * (1 + 1/2^(s-2) + 7/4^s). (End)
G.f.: (6 + x + 5*x^2 + x^3 + 6*x^4)/(1 - x^4). - Stefano Spezia, Jul 27 2025

A176524 Decimal expansion of sqrt(235).

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 23 2010

Keywords

Comments

Continued fraction expansion of sqrt(235) is A040219.

Examples

			sqrt(235) = 15.32970971675589165655...
		

Crossrefs

Cf. A002163 (decimal expansion of sqrt(5)), A010501 (decimal expansion of sqrt(47)), A176523 (decimal expansion of (45+3*sqrt(235))/10), A040219 (15 followed by (repeat 3, 30)).

Programs

  • Mathematica
    RealDigits[Sqrt[235],10,120][[1]] (* Harvey P. Dale, Mar 12 2015 *)

A041080 Numerators of continued fraction convergents to sqrt(47).

Original entry on oeis.org

6, 7, 41, 48, 617, 665, 3942, 4607, 59226, 63833, 378391, 442224, 5685079, 6127303, 36321594, 42448897, 545708358, 588157255, 3486494633, 4074651888, 52382317289, 56456969177, 334667163174, 391124132351, 5028156751386, 5419280883737, 32124561170071
Offset: 0

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Crossrefs

Programs

Formula

G.f.: -(x^7-6*x^6+7*x^5-41*x^4-48*x^3-41*x^2-7*x-6) / (x^8-96*x^4+1). - Colin Barker, Nov 04 2013

Extensions

More terms from Colin Barker, Nov 04 2013

A041081 Denominators of continued fraction convergents to sqrt(47).

Original entry on oeis.org

1, 1, 6, 7, 90, 97, 575, 672, 8639, 9311, 55194, 64505, 829254, 893759, 5298049, 6191808, 79599745, 85791553, 508557510, 594349063, 7640746266, 8235095329, 48816222911, 57051318240, 733432041791, 790483360031, 4685848841946, 5476332201977, 70401835265670
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    I:=[1, 1, 6, 7, 90, 97, 575, 672]; [n le 8 select I[n] else 96*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 11 2013
  • Mathematica
    Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[47],n]]],{n,1,50}] (* Vladimir Joseph Stephan Orlovsky, Mar 22 2011 *)
    CoefficientList[Series[(1 + x + 6 x^2 + 7 x^3 - 6 x^4 + x^5 - x^6)/(x^8 - 96 x^4 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 11 2013 *)

Formula

G.f.: -(x^2-x-1)*(x^4+7*x^2+1) / (x^8-96*x^4+1). - Colin Barker, Nov 12 2013
a(n) = 96*a(n-4) - a(n-8). - Vincenzo Librandi, Dec 11 2013

Extensions

More terms from Colin Barker, Nov 12 2013
Showing 1-5 of 5 results.