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.

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A145960 Decimal expansion of 2*log(5/3) used in BBP Pi formula.

Original entry on oeis.org

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

Views

Author

Artur Jasinski, Oct 25 2008

Keywords

Comments

BBP formula for Pi = 4*A145963 - (1/2)*A145960 - (1/2)*(A145961-A145962).

Examples

			1.021651247531981366411...
		

Crossrefs

Programs

  • Mathematica
    First[RealDigits[2 Log[5/3], 10, 100]]
  • PARI
    2*log(5/3) \\ Michel Marcus, Apr 05 2015

Formula

Equals 2*log(5/3) = 2*(log(5)-log(3)) = 2*(A016628 - A002391) = log(25/9) = 4*arctanh(1/4).
Equals Hypergeometric2F1(1, 1/2, 3/2, 1/16).
Equals Sum_{k>=0} (1/16)^k*(1/(2k+1)).

A379324 Decimal expansion of log(6)^(log(5)^(log(4)^(log(3)^log(2)))).

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Dec 20 2024

Keywords

Comments

This is an approximation to Pi accurate to 5 digits.

Examples

			3.1415773871691905336574449813486768105453105619...
		

Crossrefs

Programs

  • Mathematica
    First[RealDigits[Log[6]^Log[5]^Log[4]^Log[3]^Log[2], 10, 100]]

Formula

A016638 Decimal expansion of log(15).

Original entry on oeis.org

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

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Author

Keywords

Examples

			2.708050201102210065996004570148713344173091912091267173647342225111673....
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 2.

Crossrefs

Cf. A016443 (continued fraction).

Programs

  • Mathematica
    RealDigits[Log[15], 10, 120][[1]] (* Vincenzo Librandi, Jun 21 2015 *)
  • PARI
    default(realprecision, 20080); x=log(15); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b016638.txt", n, " ", d)); \\ Harry J. Smith, May 16 2009

Formula

Equals A002391 + A016628. - R. J. Mathar, Jun 10 2024

Extensions

Final digits of sequence corrected using the b-file. - N. J. A. Sloane, Aug 30 2009

A016648 Decimal expansion of log(25).

Original entry on oeis.org

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

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Author

Keywords

Examples

			3.218875824868200749201518666452375279051202708537035443825295782948357....
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 2.

Crossrefs

Cf. A000045, A016453 (continued fraction), A016628.

Programs

  • Mathematica
    RealDigits[Log[25], 10, 120][[1]] (* Vincenzo Librandi, Jun 21 2015 *)
  • PARI
    default(realprecision, 20080); x=log(25); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b016648.txt", n, " ", d)); \\ Harry J. Smith, May 19 2009

Formula

Equals 10 * Sum_{k>=1} F(k)^2/(k * 4^k), where F(k) is the k-th Fibonacci number (A000045). - Amiram Eldar, Aug 09 2020
Equals 2*A016628. - Alois P. Heinz, Aug 07 2023

A016579 Decimal expansion of log(5/2).

Original entry on oeis.org

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

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Author

Keywords

Examples

			0.916290731874155065183527211768011071450101219908262467791967881980785...
		

Crossrefs

Cf. A016530 (continued fraction).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); Log(5/2); // Vincenzo Librandi, Apr 07 2020
  • Mathematica
    RealDigits[Log[5/2], 10, 120][[1]] (* Vincenzo Librandi, Apr 07 2020 *)
  • PARI
    default(realprecision, 20080); x=10*log(5/2); for (n=0, 20000, d=floor(x); x=(x-d)*10; write("b016579.txt", n, " ", d)); \\ Harry J. Smith, May 25 2009
    

Formula

Equals A016628 minus A002162. - R. J. Mathar, Jan 23 2009
log(5/2) = 2*Sum_{n >= 1} 1/(n*P(n, 7/3)*P(n-1, 7/3)), where P(n, x) denotes the n-th Legendre polynomial. The first 20 terms of the series gives the approximation log(5/2) = 0.916290731874155065183527(19...), correct to 24 decimal places. - Peter Bala, Mar 18 2024

Extensions

Leading zero removed and offset adjusted by R. J. Mathar, Feb 06 2009

A016668 Decimal expansion of log(45).

Original entry on oeis.org

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

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Author

Keywords

Examples

			3.806662489770319757391249807071239048820582469914016625382036558749167....
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 2.

Crossrefs

Cf. A016473 (continued fraction).

Programs

  • Mathematica
    RealDigits[Log[45], 10, 120][[1]] (* Vincenzo Librandi, Jun 21 2015 *)
  • PARI
    default(realprecision, 20080); x=log(45); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b016668.txt", n, " ", d)); \\ Harry J. Smith, May 21 2009

Formula

Equals 2*A002391 + A016628. - R. J. Mathar, Jun 07 2024

A016673 Decimal expansion of log(50).

Original entry on oeis.org

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

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Author

Keywords

Examples

			3.912023005428146058618750787910551847126702842897290697945975792441751....
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 2.

Crossrefs

Cf. A016478 (continued fraction).

Programs

  • Mathematica
    RealDigits[Log[50], 10, 120][[1]] (* Vincenzo Librandi, Jun 21 2015 *)
  • PARI
    default(realprecision, 20080); x=log(50); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b016673.txt", n, " ", d)); \\ Harry J. Smith, May 21 2009

Formula

Equals A002162 + 2*A016628. - R. J. Mathar, Jun 07 2024

A016678 Decimal expansion of log(55).

Original entry on oeis.org

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

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Author

Keywords

Examples

			4.007333185232470918662702911191316939347308208205934897131215600604752....
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 2.

Crossrefs

Cf. A016483 (continued fraction).

Programs

  • Mathematica
    RealDigits[Log[55], 10, 120][[1]] (* Vincenzo Librandi, Jun 21 2015 *)
  • PARI
    default(realprecision, 20080); x=log(55); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b016678.txt", n, " ", d)); \\ Harry J. Smith, May 22 2009

Formula

Equals A016628+A016634. - R. J. Mathar, Jun 07 2024

A016683 Decimal expansion of log(60).

Original entry on oeis.org

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

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Author

Keywords

Examples

			4.094344562222100684830468813065066480324092180811777681888702244098460....
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 2.

Crossrefs

Cf. A016488 (continued fraction).

Programs

  • Mathematica
    RealDigits[Log[60], 10, 120][[1]] (* Vincenzo Librandi, Jun 21 2015 *)
  • PARI
    default(realprecision, 20080); x=log(60); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b016683.txt", n, " ", d)); \\ Harry J. Smith, May 22 2009

Formula

Equals 2*A002162+A002391+A016628. - R. J. Mathar, Jul 22 2025

A068434 Expansion of log(5) in base 2.

Original entry on oeis.org

1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1
Offset: 1

Views

Author

Benoit Cloitre, Mar 09 2002

Keywords

Crossrefs

Cf. A016628.

Programs

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