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.

A248267 Egyptian fraction representation of sqrt(41) (A010495) using a greedy function.

Original entry on oeis.org

6, 3, 15, 321, 111450, 533909816159, 325998701518914099105001, 1006914879088411198399682064005635831534437484321, 1497711655729721286088828059704410216184274677681054392262396421340070136379357931802690267613686
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[ 41]]

A041068 Numerators of continued fraction convergents to sqrt(41).

Original entry on oeis.org

6, 13, 32, 397, 826, 2049, 25414, 52877, 131168, 1626893, 3384954, 8396801, 104146566, 216689933, 537526432, 6667007117, 13871540666, 34410088449, 426792602054, 887995292557, 2202783187168, 27321393538573
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

Formula

G.f.: -(x^5-6*x^4+13*x^3+32*x^2+13*x+6) / (x^6+64*x^3-1). - Colin Barker, Nov 04 2013

A041069 Denominators of continued fraction convergents to sqrt(41).

Original entry on oeis.org

1, 2, 5, 62, 129, 320, 3969, 8258, 20485, 254078, 528641, 1311360, 16264961, 33841282, 83947525, 1041211582, 2166370689, 5373952960, 66653806209, 138681565378, 344016936965, 4266884808958, 8877786554881, 22022457918720, 273147281579521, 568317021077762
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    I:=[1, 2, 5, 62, 129, 320]; [n le 6 select I[n] else 64*Self(n-3)+Self(n-6): n in [1..30]]; // Vincenzo Librandi, Dec 10 2013
  • Mathematica
    Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[41], n]]], {n, 1, 50}] (* Vladimir Joseph Stephan Orlovsky, Mar 21 2011 *)
    Denominator[Convergents[Sqrt[41], 30]] (* Vincenzo Librandi, Dec 10 2013 *)
    LinearRecurrence[{0,0,64,0,0,1},{1,2,5,62,129,320},40] (* Harvey P. Dale, Jun 19 2022 *)

Formula

G.f.: -(x^4-2*x^3+5*x^2+2*x+1) / (x^6+64*x^3-1). - Colin Barker, Nov 12 2013
a(n) = 64*a(n-3) + a(n-6). - Vincenzo Librandi, Dec 10 2013

Extensions

More terms from Colin Barker, Nov 12 2013

A010133 Continued fraction for sqrt(41).

Original entry on oeis.org

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

Views

Author

Keywords

Examples

			6.40312423743284868648821767... = 6 + 1/(2 + 1/(2 + 1/(12 + 1/(2 + ...)))). - _Harry J. Smith_, Jun 05 2009
		

References

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

Crossrefs

Cf. A010495 (decimal expansion).
Cf. A041068/A041069 (convergents), A248267 (Egyptian fraction).

Programs

  • Mathematica
    ContinuedFraction[Sqrt[41],300] (* Vladimir Joseph Stephan Orlovsky, Mar 06 2011 *)
  • PARI
    { allocatemem(932245000); default(realprecision, 25000); x=contfrac(sqrt(41)); for (n=0, 20000, write("b010133.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 05 2009

Formula

From Elmo R. Oliveira, Aug 03 2024: (Start)
G.f.: 2*(3 + x + x^2 + 3*x^3)/((1 - x)*(1 + x + x^2)).
a(n) = a(n-3), n > 3. (End)

A011035 Decimal expansion of 4th root of 41.

Original entry on oeis.org

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

Views

Author

Keywords

Crossrefs

Cf. A010495.

Programs

Showing 1-5 of 5 results.