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 1-7 of 7 results.

A002951 Continued fraction for fifth root of 5.

Original entry on oeis.org

1, 2, 1, 1, 1, 2, 1, 2, 8, 1, 25, 1, 5, 1, 22, 1, 8, 1, 1, 9, 1, 1, 4, 1, 2, 1, 2, 1, 2, 2, 1, 1, 1, 1, 2, 1, 6, 2, 46, 1, 12, 1, 32, 1, 2, 3, 2, 3, 55, 1, 12, 3, 8, 1, 1, 11, 1, 4, 1, 1, 1, 2, 1, 1, 7, 1, 1, 4, 3, 3, 3218, 1, 3, 1, 2, 2, 3, 1, 1, 2, 11, 1, 7, 57, 2, 2, 2, 2, 1, 1, 67, 1, 2, 3, 1, 1, 13, 3
Offset: 0

Views

Author

Keywords

Comments

Fifth root of 5 = 5^(1/5). - Harry J. Smith, May 10 2009

Examples

			1.379729661461214832390063464... = 1 + 1/(2 + 1/(1 + 1/(1 + 1/(1 + ...)))). - _Harry J. Smith_, May 10 2009
		

References

  • H. P. Robinson, Letter to N. J. A. Sloane, Nov 13 1973.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A005534 (decimal expansion).
Cf. A002363, A002364 (convergents).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); ContinuedFraction(5^(1/5)); // G. C. Greubel, Nov 02 2018
  • Maple
    with(numtheory): cfrac(5^(1/5),100,'quotients'); # Muniru A Asiru, Nov 02 2018
  • Mathematica
    ContinuedFraction[5^(1/5), 100] (* G. C. Greubel, Nov 02 2018 *)
  • PARI
    { allocatemem(932245000); default(realprecision, 21000); x=contfrac(5^(1/5)); for (n=1, 20000, write("b002951.txt", n-1, " ", x[n])); } \\ Harry J. Smith, May 10 2009
    

Extensions

More terms copied from Smith's b-file by Hagen von Eitzen, Jul 20 2009
Offset changed by Andrew Howroyd, Jul 05 2024

A002363 Denominators of continued fraction convergents to fifth root of 5.

Original entry on oeis.org

1, 2, 3, 5, 8, 21, 29, 79, 661, 740, 19161, 19901, 118666, 138567, 3167140, 3305707, 29612796, 32918503, 62531299, 595700194, 658231493, 1253931687, 5673958241, 6927889928, 19529738097, 26457628025, 72444994147, 98902622172, 270250238491, 639403099154
Offset: 0

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Author

Keywords

References

  • D. H. Lehmer, Guide to Tables in the Theory of Numbers. Bulletin No. 105, National Research Council, Washington, DC, 1941, p. 67.
  • P. Seeling, Verwandlung der irrationalen Groesse ... in einen Kettenbruch, Archiv. Math. Phys., 46 (1866), 80-120.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Numerators in A002364.

Programs

  • Maple
    numtheory:-cfrac(5^(1/5),1000,'con'):
    map(denom,con); # Robert Israel, May 13 2018
  • Mathematica
    Denominator[Convergents[Surd[5,5],30]] (* Harvey P. Dale, Jul 16 2016 *)

Extensions

More terms from Herman P. Robinson
More terms from Harvey P. Dale, Jul 16 2016
Offset changed by Andrew Howroyd, Jul 05 2024

A002364 Numerators of continued fraction convergents to fifth root of 5.

Original entry on oeis.org

1, 3, 4, 7, 11, 29, 40, 109, 912, 1021, 26437, 27458, 163727, 191185, 4369797, 4560982, 40857653, 45418635, 86276288, 821905227, 908181515, 1730086742, 7828528483, 9558615225, 26945758933, 36504374158, 99954507249, 136458881407, 372872270063, 882203421533
Offset: 0

Views

Author

Keywords

References

  • D. H. Lehmer, Guide to Tables in the Theory of Numbers. Bulletin No. 105, National Research Council, Washington, DC, 1941, p. 67.
  • P. Seeling, Verwandlung der irrationalen Groesse ... in einen Kettenbruch, Archiv. Math. Phys., 46 (1866), 80-120.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A002363 (denominators), A002951 A005534.

Programs

  • Mathematica
    Numerator[Convergents[Surd[5,5],30]] (* Harvey P. Dale, Dec 06 2015 *)

Extensions

Definition clarified by and more terms from Harvey P. Dale, Dec 06 2015
Offset changed by Andrew Howroyd, Jul 05 2024

A011100 Decimal expansion of 5th root of 15.

Original entry on oeis.org

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

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Author

Keywords

Examples

			1.7187719275874787770135214520444...
		

Programs

Formula

Equals A005532 * A005534 . - R. J. Mathar, May 22 2024

A011130 Decimal expansion of 5th root of 45.

Original entry on oeis.org

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

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Author

Keywords

Programs

Formula

Equals A011094*A005534. - R. J. Mathar, Dec 17 2024

A337840 a(n) is the decimal place of the start of the first occurrence of n in the decimal expansion of n^(1/n).

Original entry on oeis.org

0, 4, 10, 1, 38, 6, 9, 4, 12, 17, 26, 0, 264, 144, 107, 101, 101, 4, 78, 68, 36, 86, 11, 17, 147, 151, 205, 50, 55, 26, 307, 88, 94, 180, 177, 61, 113, 244, 280, 37, 110, 38, 285, 101, 124, 223, 243, 25, 86, 116, 66, 77, 146, 283, 3, 60, 20, 82, 27, 146, 82, 140
Offset: 1

Views

Author

William Phoenix Marcum, Sep 25 2020

Keywords

Comments

Does a(n) exist for all n? Some relatively large values: a(1021) = 67714, a(1111) = 64946. - Chai Wah Wu, Oct 07 2020

Examples

			For n = 1, 1^(1/1) = 1.0000000, so a(1) is 0.
For n = 12, 12^(1/12) ~= 1.2300755, so a(12) = 0.
		

Crossrefs

Cf. A177715.
Decimal expansions of some n^(1/n): A002193, A002581, A005534, A011215, A011231, A011247, A011263, A011279, A011295, A011311, A011327, A011343, A011359.

Programs

  • Mathematica
    max = 3000; a[n_] := SequencePosition[RealDigits[n^(1/n), 10, max][[1]], IntegerDigits[n]][[1, 1]] - 1; Array[a, 100] (* Amiram Eldar, Sep 25 2020 *)
  • PARI
    a(n) = {if (n==1, 0, my(p=10000); default(realprecision, p+1); my(x = floor(10^p*n^(1/n)), d = digits(x), nb = #Str(n)); for(k=1, #d-nb+1, my(v=vector(nb, i, d[k+i-1])); if (fromdigits(v) == n, return(k-1));); error("not found"););} \\ Michel Marcus, Sep 30 2020
    
  • Python
    import gmpy2
    from gmpy2 import mpfr, digits, root
    gmpy2.get_context().precision=10**5
    def A337840(n): # increase precision if -1 is returned
        return digits(root(mpfr(n),n))[0].find(str(n)) # Chai Wah Wu, Oct 07 2020

Extensions

More terms from Amiram Eldar, Sep 25 2020

A281143 Decimal expansion of 10!^(1/10).

Original entry on oeis.org

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

Views

Author

Robert G. Wilson v, Jan 15 2017

Keywords

Comments

Base b such that log_b 10! = 10.
Inspired by the idea of utilizing the log scaled to 10! being 10, i.e., log_b 10! = 10, therefore b = 2^(4/5)*3^(2/5)*5^(1/5)*7^(1/10).

Examples

			4.52872868811676476220330933719550879349863167608939046288611476046926255...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[2^(4/5) 3^(2/5) 5^(1/5) 7^(1/10), 10, 111][[1]] (* or *)
    RealDigits[Solve[Log[b, 10!] == 10, b][[1, 1, 2]], 10, 105][[1]]

Formula

Showing 1-7 of 7 results.