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 1-2 of 2 results.

A010135 Continued fraction for sqrt(45).

Original entry on oeis.org

6, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2, 2, 2, 1, 12, 1, 2
Offset: 0

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Keywords

Examples

			6.708203932499369089227521006... = 6 + 1/(1 + 1/(2 + 1/(2 + 1/(2 + ...)))). - _Harry J. Smith_, Jun 06 2009
		

References

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

Crossrefs

Cf. A010499 (decimal expansion), A041076/A041077 (convergents).

Programs

  • Mathematica
    ContinuedFraction[Sqrt[45],300] (* Vladimir Joseph Stephan Orlovsky, Mar 07 2011 *)
  • PARI
    { allocatemem(932245000); default(realprecision, 17000); x=contfrac(sqrt(45)); for (n=0, 20000, write("b010135.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 06 2009

Formula

G.f.: (6 + x + 2*x^2 + 2*x^3 + 2*x^4 + x^5 + 6*x^6)/(1 - x^6). - Stefano Spezia, Jul 27 2025

A041077 Denominators of continued fraction convergents to sqrt(45).

Original entry on oeis.org

1, 1, 3, 7, 17, 24, 305, 329, 963, 2255, 5473, 7728, 98209, 105937, 310083, 726103, 1762289, 2488392, 31622993, 34111385, 99845763, 233802911, 567451585, 801254496, 10182505537, 10983760033, 32150025603, 75283811239, 182717648081, 258001459320, 3278735159921
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[45],n]]],{n,1,50}] (* Vladimir Joseph Stephan Orlovsky, Mar 22 2011*)
    Denominator[Convergents[Sqrt[45], 30]] (* Vincenzo Librandi, Oct 24 2013 *)
    LinearRecurrence[{0,0,0,0,0,322,0,0,0,0,0,-1},{1,1,3,7,17,24,305,329,963,2255,5473,7728},40] (* Harvey P. Dale, Jun 11 2022 *)

Formula

a(n) = 322*a(n-6)-a(n-12). G.f.: -(x^10-x^9+3*x^8-7*x^7+17*x^6-24*x^5-17*x^4-7*x^3-3*x^2-x-1)/((x^2-3*x+1)*(x^2+3*x+1)*(x^4-3*x^3+8*x^2-3*x+1)*(x^4+3*x^3+8*x^2+3*x+1)). [Colin Barker, Jul 18 2012]

Extensions

More terms from Vincenzo Librandi, Oct 24 2013
Showing 1-2 of 2 results.