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 1-10 of 13 results. Next

A120028 Continued fraction expansion of the value of Minkowski's question mark function at Levy's constant (Exp[Pi^2/(12*Log[2])], A086702).

Original entry on oeis.org

3, 6, 10, 2, 8388607, 1, 1, 10, 5, 1, 19802808501020211999048785114, 1, 5, 1, 5, 2, 2, 10, 4, 1, 142, 3, 1, 1, 1, 1, 1, 2, 13, 16, 1, 83, 2, 4, 1, 15, 1, 62, 1, 20, 1, 2, 1, 1, 1, 9, 1, 1, 1, 13, 2, 3, 1, 4, 1, 5, 1, 1, 1, 5, 7, 1, 27, 1, 2, 4, 3, 1, 3, 3, 1, 7, 2, 1, 1, 91, 11, 1, 2, 4, 4
Offset: 0

Views

Author

Joseph Biberstine (jrbibers(AT)indiana.edu), Jun 04 2006

Keywords

Comments

a[92] has over 150 decimal digits, making 750332738256083509758042341909438953923620244270237443771885409340366143805720089/2^267 an excellent approximation to the constant.

Crossrefs

Cf. A120029.

Programs

  • Mathematica
    ContinuedFraction[cf = ContinuedFraction[Exp[Pi^2/(12*Log[2])], 50(*arbitrary precision*)]; IntegerPart[Exp[Pi^2/(12*Log[2])]] + Sum[(-1)^(k)/2^(Sum[cf[[i]], {i, 2, k}] - 1), {k, 2, Length[cf]}]]

A120029 Decimal expansion of the value of Minkowski's question mark function at Levy's constant (Exp[Pi^2/(12*Log[2])], A086702).

Original entry on oeis.org

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

Views

Author

Joseph Biberstine (jrbibers(AT)indiana.edu), Jun 04 2006

Keywords

Comments

a[92] has over 150 decimal digits, making 750332738256083509758042341909438953923620244270237443771885409340366143805720089/2^267 an excellent approximation to the constant.

Examples

			3.164062499992724042385816574096679687499999999999997...
		

Crossrefs

Cf. A120028.

Programs

  • Mathematica
    RealDigits[cf = ContinuedFraction[Exp[Pi^2/(12*Log[2])], 50(*arbitrary precision*)]; IntegerPart[Exp[Pi^2/(12*Log[2])]] + Sum[(-1)^(k)/2^(Sum[cf[[i]], {i, 2, k}] - 1), {k, 2, Length[cf]}], 10, 100]

A100199 Decimal expansion of Pi^2/(12*log(2)), inverse of Levy's constant.

Original entry on oeis.org

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

Views

Author

Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Dec 27 2004

Keywords

Comments

From A.H.M. Smeets, Jun 12 2018: (Start)
The denominator of the k-th convergent obtained from a continued fraction of a constant, the terms of the continued fraction satisfying the Gauss-Kuzmin distribution, will tend to exp(k*A100199).
Similarly, the error between the k-th convergent obtained from a continued fraction of a constant, and the constant itself will tend to exp(-2*k*A100199). (End)
The term "Lévy's constant" is sometimes used to refer to this constant (Wikipedia). - Bernard Schott, Sep 01 2022

Examples

			1.1865691104156254528217229759472371205683565364720543359542542986528...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 1.7, p. 54.

Crossrefs

Programs

Formula

Equals 1/A089729 = log(A086702) = A174606/2.
Equals ((Pi^2)/12)/log(2) = A072691 / A002162 = (Sum_{n>=1} ((-1)^(n+1))/n^2) / (Sum_{n>=1} ((-1)^(n+1))/n^1). - Terry D. Grant, Aug 03 2016
Equals (-1/log(2)) * Integral_{x=0..1} log(x)/(1+x) dx (from Corless, 1992). - Bernard Schott, Sep 01 2022

A084407 Number of decimal places to which the n-th convergent of continued fraction expansion of Pi matches with the correct value.

Original entry on oeis.org

0, 2, 4, 6, 9, 9, 9, 9, 11, 10, 12, 12, 14, 15, 15, 16, 17, 17, 18, 19, 21, 23, 24, 24, 25, 27, 29, 30, 30, 32, 33, 34, 37, 39, 40, 40, 41, 42, 44, 45, 45, 46, 47, 49, 50, 51, 51, 53, 54, 55, 55, 56, 56, 58, 59, 59, 60, 60, 61, 60, 62, 64, 63, 64, 65, 65, 67, 67, 68, 70, 69, 71
Offset: 1

Views

Author

Lekraj Beedassy, Jun 24 2003

Keywords

Comments

The n-th convergent of the continued fraction expansion of Pi is A002485(n+1)/A002486(n+1).

Examples

			From _A.H.M. Smeets_, Jun 13 2018: (Start)
Pi = 3.141592653589...
n=1: 3/1 = 3.0... so a(1) = 0;
n=2: 22/7 = 3.142... so a(2) = 2;
n=3: 333/106 = 3.14150... so a(3) = 4;
n=4: 355/113 = 3.1415929... so a(4) = 6;
n=5: 103993/33102 = 3.1415926530... so a(5) = 9;
n=6: 104348/33215 = 3.1415926539... so a(6) = 9;
n=7: 208341/66317 = 3.1415926534... so a(7) = 9;
n=8: 312689/99532 = 3.1415926536... so a(8) = 9;
n=9: 833719/265381 = 3.141592653581... so a(9) = 11;
n=10: 1146408/364913 = 3.14159265359... so a(10) = 10. (End)
		

Crossrefs

Formula

Limit_{n -> oo} a(n)/n = 2*log(A086702)/log(10) = 2*A100199/log(10) = 2*A240995. - A.H.M. Smeets, Jun 13 2018

Extensions

More terms from Vladeta Jovovic, Jun 27 2003

A089729 Decimal expansion of Levy's constant 12*log(2)/Pi^2.

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Jan 19 2004

Keywords

Comments

For x>y in [1..n], the average number of loop steps of the Euclid Algorithm for GCD (over all choices x, y) is asymptotic to k*log(n) where k is this constant. See Crandall & Pomerance. - Michel Marcus, Mar 23 2016

Examples

			0.8427659132721945169072631939639641155945183893191504965...
		

References

  • R. Crandall and C. Pomerance, Prime Numbers: A Computational Perspective, Springer, NY, 2001; see Theorem 2.1.3, p. 84.
  • S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 156.

Crossrefs

Programs

  • Mathematica
    RealDigits[12 Log[2]/Pi^2, 10, 100][[1]] (* Bruno Berselli, Jun 20 2013 *)
  • PARI
    12*log(2)/Pi^2 \\ Michel Marcus, Mar 23 2016

Extensions

Leading zero removed by R. J. Mathar, Feb 05 2009

A305879 Number of binary places to which n-th convergent of continued fraction expansion of Pi matches the correct value.

Original entry on oeis.org

2, 8, 13, 21, 28, 31, 28, 34, 32, 38, 40, 44, 47, 51, 52, 54, 57, 60, 62, 64, 70, 78, 80, 81, 84, 91, 94, 100, 103, 104, 107, 116, 121, 132, 133, 136, 133, 144, 148, 152, 148, 156, 158, 165, 167, 170, 173, 176, 179, 182
Offset: 1

Views

Author

A.H.M. Smeets, Jun 13 2018

Keywords

Comments

For the similar case of number of correct decimal places see A084407.
The denominator of the k-th convergent obtained from a continued fraction satisfying the Gauss-Kuzmin distribution will tend to exp(k*A100199), A100199 being the inverse of Lévy's constant; the error between the k-th convergent and the constant itself tends to exp(-2*k*A100199), or in binary digits 2*k*A100199/log(2) bits after the binary point.
The sequence for quaternary digits is obtained by floor(a(n)/2), the sequence for octal digits is obtained by floor(a(n)/3), the sequence for hexadecimal digits is obtained by floor(a(n)/4).

Examples

			Pi = 11.0010010000111111...
n=1: 3/1 = 11.000... so a(1) = 2
n=2: 22/7 = 11.001001001... so a(2) = 8
n=3: 333/106 = 11.00100100001110... so a(3) = 13
		

Crossrefs

Formula

Lim {n -> oo} (a(n)/n) = 2*log(A086702)/log(2) = 2*A100199/log(2) = 2*A305607.

A317557 Number of binary digits to which the n-th convergent of the continued fraction expansion of log(2) matches the correct value.

Original entry on oeis.org

0, -1, 3, 6, 9, 13, 14, 17, 19, 20, 23, 20, 25, 20, 33, 37, 35, 38, 41, 43, 45, 43, 47, 48, 52, 54, 58, 61, 68, 70, 74, 77, 78, 81, 86, 89, 92, 93, 92, 99, 105, 109, 113, 116, 118, 121, 127, 133, 136, 135, 139, 141, 145, 149, 154, 159, 161, 165, 171, 173, 172, 180
Offset: 1

Views

Author

A.H.M. Smeets, Jul 31 2018

Keywords

Comments

Binary expansion of log(2) in A068426.
For number of correct decimal digits see A317558.
For the similar case of number of correct binary digits of Pi see A305879.
The denominator of the k-th convergent obtained from a continued fraction satisfying the Gauss-Kuzmin distribution will tend to exp(k*A100199), A100199 being the inverse of Lévy's constant; the error between the k-th convergent and the constant itself tends to exp(-2*k*A100199), or in binary digits 2*k*A100199/log(2) bits after the binary point.
The sequence for quaternary digits is obtained by floor(a(n)/2), the sequence for octal digits is obtained by floor(a(n)/3), and the sequence for hexadecimal digits is obtained by floor(a(n)/4).

Examples

			   n   convergent         binary expansion         a(n)
  ==  ============  =============================  ====
   1     0 / 1      0.0                              0
   2     1 / 1      1.0                             -1
   3     2 / 3      0.1010...                        3
   4     7 / 10     0.1011001...                     6
   5     9 / 13     0.1011000100...                  9
   6    61 / 88     0.10110001011101...             13
   7   192 / 277    0.101100010111000...            14
   8   253 / 365    0.101100010111001001...         17
   9   445 / 642    0.10110001011100100000...       19
  10  1143 / 1649   0.101100010111001000011...      20
  oo  lim = log(2)  0.101100010111001000010111...   --
		

Crossrefs

Programs

  • Mathematica
    a[n_] := Block[{k = 1, a = RealDigits[ Log@2, 2, 4 + 10][[1]], b = RealDigits[ FromContinuedFraction@ ContinuedFraction[Log@2, n + 1], 2, 4n + 10][[1]]}, While[ a[[k]] == b[[k]], k++]; k - 1]; a[1] = 0; a[2] = -1; Array[a, 61] (* Robert G. Wilson v, Aug 09 2018 *)

Formula

Lim_{n -> oo} a(n)/n = 2*log(A086702)/log(2) = 2*A100199/log(2) = 2*A305607.

Extensions

a(40) onward from Robert G. Wilson v, Aug 09 2018

A317558 Number of decimal digits to which the n-th convergent of the continued fraction expansion of log(2) matches the correct value.

Original entry on oeis.org

0, -1, 1, 0, 2, 4, 5, 4, 5, 6, 6, 6, 7, 8, 9, 10, 11, 10, 12, 13, 13, 13, 14, 15, 15, 16, 17, 18, 20, 22, 22, 23, 23, 24, 25, 26, 27, 27, 28, 29, 31, 32, 33, 34, 35, 36, 38, 40, 39, 41, 39, 43, 44, 45, 46, 48, 48, 49, 51, 52, 52, 54, 54, 55, 55, 56, 57, 57, 58
Offset: 1

Views

Author

A.H.M. Smeets, Jul 31 2018

Keywords

Comments

Decimal expansion of log(2) in A002162.
For the number of correct binary digits see A317557.
For the similar case of number of correct decimal digits of Pi see A084407.

Examples

			   n   convergent    decimal expansion    a(n)
  ==  ============  ====================  ====
   1     0 / 1      0.0                     0
   2     1 / 1      1.0                    -1
   3     2 / 3      0.66...                 1
   4     7 / 10     0.7...                  0
   5     9 / 13     0.692...                2
   6    61 / 88     0.69318...              4
   7   192 / 277    0.693140...             5
   8   253 / 365    0.69315...              4
   9   445 / 642    0.693146...             5
  10  1143 / 1649   0.6931473...            6
  oo  lim = log(2)  0.693147180559945...   --
		

Crossrefs

Programs

  • Mathematica
    a[n_] := Block[{k = 1, a = RealDigits[Log@2, 10, n + 10][[1]], b = RealDigits[ FromContinuedFraction@ ContinuedFraction[ Log@2, n], 10, n + 10][[1]]}, While[a[[k]] == b[[k]], k++]; k - 1]; a[1] = 0; a[2] = -1; Array[a, 69] (* Robert G. Wilson v, Aug 09 2018 *)

Formula

Lim_{n -> oo} a(n)/n = 2*log(A086702)/log(10) = 2*A100199/log(10) = 2*A240995.

Extensions

a(61) onward from Robert G. Wilson v, Aug 09 2018

A174606 Decimal expansion of Pi^2/(6*log 2).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Mar 23 2010

Keywords

Examples

			2.37313822083125090564344595....
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 1.8.1, p. 62.

Crossrefs

Programs

  • Mathematica
    RealDigits[Pi^2/(6*Log[2]), 10, 100][[1]] (* Amiram Eldar, May 24 2023 *)
  • PARI
    Pi^2/6/log(2) \\ Michel Marcus, Apr 04 2014

Formula

Equals 2*log(A086702). - Jean-François Alcover, Apr 15 2014
Equals 2*A100199. - Hugo Pfoertner, Nov 18 2024

A317907 Number of binary places to which n-th convergent of continued fraction expansion of Khintchine's constant matches the correct value.

Original entry on oeis.org

0, -1, 5, 3, 9, 8, 12, 14, 16, 22, 25, 27, 30, 33, 39, 44, 42, 49, 52, 51, 56, 55, 64, 70, 73, 77, 81, 83, 82, 85, 88, 92, 93, 99, 101, 104, 109, 104, 111, 114, 117, 120, 122, 124, 126, 129, 131, 133, 136, 139, 138, 144, 138, 148, 151, 150, 153, 156, 158, 162
Offset: 1

Views

Author

A.H.M. Smeets, Aug 10 2018

Keywords

Comments

For number of correct decimal digits see A317908.
For the similar case of number of correct binary digits of Pi see A305879.
For the similar case of number of correct binary digits of log(2) see A317557.
The denominator of the k-th convergent obtained from a continued fraction satisfying the Gauss-Kuzmin distribution will tend to exp(k*A100199), A100199 being the inverse of Lévy's constant; the error between the k-th convergent and the constant itself tends to exp(-2*k*A100199), or in binary digits 2*k*A100199/log(2) bits after the binary point.
The sequence for quaternary digits is obtained by floor(a(n)/2), the sequence for octal digits is obtained by floor(a(n)/3), and the sequence for hexadecimal digits is obtained by floor(a(n)/4).

Examples

			   n   convergent         binary expansion       a(n)
  ==  =============  ==========================  ====
   1     2 / 1       10.0...                       0
   2     3 / 1       11.0...                      -1
   3     8 / 3       10.101010...                  5
   4    43 / 16      10.1011...                    3
   5    51 / 19      10.1010111100...              9
  oo  lim = A317906  10.101011110111100111...     --
		

Crossrefs

Programs

  • Python
    i,cf = 0,[]
    while i <= 20100:
        c = A002211(i)
        cf,i = cf+[c],i+1
    p0,p1,q0,q1,i,base = cf[0],1,1,0,1,2
    while i <= 20100:
        p0,p1,q0,q1,i = cf[i]*p0+p1,p0,cf[i]*q0+q1,q0,i+1
    a0 = p0//q0
    p0 = p0-a0*q0
    i,p0,dd = 0,p0*base,[a0]
    while i < 70000:
        d,p0,i = p0//q0,(p0%q0)*base,i+1
        dd = dd+[d]
    n,pn0,pn1,qn0,qn1 = 1,a0,1,1,0
    while n <= 20000:
        p,q = pn0,qn0
        if p//q != a0:
            print(n,"- manual!")
        else:
            i,p,di = 0,(p%q)*base,a0
            while di == dd[i]:
                i,di,p = i+1,p//q,(p%q)*base
            print(n,i-1)
        n,pn0,pn1,qn0,qn1 = n+1,cf[n]*pn0+pn1,pn0,cf[n]*qn0+qn1,qn0

Formula

Lim_{n -> oo} a(n)/n = 2*log(A086702)/log(2) = 2*A100199/log(2) = 2*A305607.
Showing 1-10 of 13 results. Next