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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A004585 Expansion of sqrt(10) in base 2.

Original entry on oeis.org

1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1
Offset: 2

Views

Author

Keywords

Crossrefs

Cf. A010467.

Programs

  • Magma
    d:= 10; m:=2; Prune(Reverse(IntegerToSequence(Isqrt(d*m^100), m))); // G. C. Greubel, Mar 25 2018
    
  • Mathematica
    RealDigits[Sqrt[10], 2, 100][[1]] (* G. C. Greubel, Mar 25 2018 *)
  • PARI
    my(b = binary(sqrt(10))); concat(b[1], b[2]) \\ Michel Marcus, Mar 26 2018

A348670 Decimal expansion of 10 - Pi^2.

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Oct 29 2021

Keywords

Comments

Let ABC be a unit-area triangle, and let P be a point uniformly picked at random inside it. Let D, E and F be the intersection points of the lines AP, BP and CP with the sides BC, CA and AB, respectively. Then, the expected value of the area of the triangle DEF is this constant.

Examples

			0.13039559891064138116550900012384886468630059275920...
		

References

  • Calvin C. Clawson, Mathematical Mysteries: The Beauty and Magic of Numbers, Springer, 2013, p. 220.
  • A. M. Mathai, An introduction to geometrical probability: distributional aspects with applications, Amsterdam: Gordon and Breach, 1999, p. 275, ex. 2.5.3.

Crossrefs

Programs

  • Mathematica
    RealDigits[10 - Pi^2, 10, 100][[1]]
  • PARI
    10 - Pi^2 \\ Michel Marcus, Oct 29 2021

Formula

Equals Sum_{k>=1} 1/(k*(k+1))^3 = Sum_{k>=1} 1/A060459(k).
Equals 6 * Sum_{k>=2} 1/(k*(k+1)^2*(k+2)) = Sum_{k>=3} 1/A008911(k).
Equals 2 * Integral_{x=0..1, y=0..1} x*(1-x)*y*(1-y)/(1-x*y)^2 dx dy.
Equals 4 * Sum_{m,n>=1} (m-n)^2/(m*n*(m+1)^2*(n+1)^2*(m+2)*(n+2)) (Sitaru, 2023). - Amiram Eldar, Aug 18 2023

A004586 Expansion of sqrt(10) in base 3.

Original entry on oeis.org

1, 0, 0, 1, 1, 1, 0, 1, 0, 2, 2, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 2, 2, 1, 2, 0, 1, 2, 0, 1, 0, 0, 1, 0, 2, 2, 1, 0, 2, 0, 2, 1, 1, 0, 2, 1, 0, 2, 0, 0, 2, 2, 2, 0, 2, 0, 0, 2, 1, 0, 1, 0, 0, 2, 0, 2, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 2, 0, 2, 1, 0, 1, 0, 0, 2, 1, 2, 0, 0, 1, 2, 0, 1, 1, 1
Offset: 2

Views

Author

Keywords

Crossrefs

Cf. A010467.

Programs

  • Magma
    d:= 10; m:=3; Prune(Reverse(IntegerToSequence(Isqrt(d*m^100), m))); // G. C. Greubel, Mar 25 2018
  • Mathematica
    RealDigits[Sqrt[10], 3, 100][[1]] (* G. C. Greubel, Mar 25 2018 *)

A004587 Expansion of sqrt(10) in base 4.

Original entry on oeis.org

3, 0, 2, 2, 1, 2, 0, 2, 3, 0, 0, 1, 3, 1, 1, 2, 3, 1, 0, 2, 3, 1, 2, 2, 2, 1, 1, 0, 2, 1, 0, 0, 0, 2, 1, 1, 0, 1, 1, 1, 3, 2, 1, 0, 0, 1, 2, 0, 1, 2, 1, 2, 3, 0, 3, 1, 3, 3, 3, 3, 1, 1, 0, 2, 2, 2, 3, 1, 0, 3, 2, 0, 0, 2, 2, 2, 3, 2, 2, 3, 3, 2, 0, 1, 2, 0, 0, 0, 0, 0, 1, 3, 0, 1, 1, 1, 3, 1, 1
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A010467.

Programs

  • Magma
    d:= 10; m:=4; Prune(Reverse(IntegerToSequence(Isqrt(d*m^100), m))); // G. C. Greubel, Mar 25 2018
  • Mathematica
    RealDigits[Sqrt[10], 4, 100][[1]] (* G. C. Greubel, Mar 25 2018 *)

A004588 Expansion of sqrt(10) in base 5.

Original entry on oeis.org

3, 0, 4, 0, 1, 2, 0, 2, 4, 3, 2, 3, 4, 1, 4, 2, 0, 3, 1, 1, 3, 2, 2, 1, 1, 2, 2, 0, 1, 2, 0, 0, 3, 2, 3, 4, 4, 4, 4, 4, 2, 3, 4, 3, 3, 2, 4, 4, 2, 4, 0, 4, 4, 1, 4, 3, 0, 3, 1, 4, 4, 1, 2, 3, 3, 1, 3, 3, 4, 2, 4, 2, 2, 2, 0, 4, 0, 3, 3, 3, 4, 1, 2, 1, 4, 2, 4, 3, 3, 0, 2, 3, 4, 4, 1, 4, 0, 3, 1
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A010467.

Programs

  • Magma
    Prune(Reverse(IntegerToSequence(Isqrt(10*5^400), 5))); // Vincenzo Librandi, Jan 23 2016
  • Mathematica
    RealDigits[Sqrt[10], 5, 100][[1]] (* Vincenzo Librandi, Jan 23 2016 *)

Extensions

a(87) onwards corrected by Sean A. Irvine, Jan 22 2016

A004589 Expansion of sqrt(10) in base 6.

Original entry on oeis.org

3, 0, 5, 5, 0, 1, 5, 1, 2, 0, 5, 3, 2, 1, 0, 3, 1, 4, 4, 3, 1, 3, 0, 2, 5, 4, 4, 5, 1, 2, 0, 1, 3, 3, 1, 0, 1, 1, 4, 3, 0, 2, 2, 4, 0, 0, 0, 2, 0, 5, 1, 4, 4, 2, 1, 0, 4, 1, 5, 4, 0, 4, 5, 2, 1, 5, 2, 0, 1, 4, 0, 0, 1, 3, 0, 2, 2, 5, 5, 1, 3, 3, 1, 5, 2, 3, 1, 0, 5, 2, 0, 0, 0, 4, 4, 3, 5, 1, 2
Offset: 1

Views

Author

Keywords

Examples

			3.0550151205321...
		

Crossrefs

Cf. A010467.

Programs

  • Magma
    Prune(Reverse(IntegerToSequence(Isqrt(10*6^400), 6))); // Vincenzo Librandi, Jan 23 2016
  • Mathematica
    RealDigits[Sqrt[10], 6, 108][[1]] (* Alonso del Arte, Jul 31 2014 *)

Extensions

a(79) onwards corrected by Sean A. Irvine, Jan 22 2016

A004590 Expansion of sqrt(10) in base 7.

Original entry on oeis.org

3, 1, 0, 6, 4, 4, 2, 5, 4, 2, 6, 3, 1, 4, 6, 1, 0, 0, 2, 5, 1, 4, 1, 5, 3, 6, 5, 3, 4, 3, 4, 6, 2, 1, 6, 3, 2, 5, 4, 0, 1, 6, 5, 2, 1, 0, 2, 1, 5, 6, 0, 6, 6, 4, 2, 6, 1, 6, 1, 0, 2, 6, 3, 2, 5, 6, 5, 4, 3, 1, 2, 1, 1, 6, 5, 5, 5, 2, 1, 3, 4, 0, 6, 5, 0, 6, 3, 2, 0, 5, 1, 1, 0, 0, 5, 1, 6, 0, 3
Offset: 1

Views

Author

Keywords

Examples

			3.106442542631461...
		

Crossrefs

Cf. A010467.

Programs

  • Magma
    Prune(Reverse(IntegerToSequence(Isqrt(10*7^200),7))); // Jason Kimberley, Feb 19 2012
  • Mathematica
    RealDigits[Sqrt[10], 7, 105][[1]] (* Alonso del Arte, Jul 31 2014 *)

Extensions

a(72) onwards corrected by Sean A. Irvine, Jan 29 2016

A004591 Expansion of sqrt(10) in base 8.

Original entry on oeis.org

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

Views

Author

Keywords

Crossrefs

Cf. A010467.

Programs

  • Magma
    Prune(Reverse(IntegerToSequence(Isqrt(10*8^200),8))); // Jason Kimberley, Feb 19 2012
  • Mathematica
    RealDigits[Sqrt[10],8,120][[1]] (* Harvey P. Dale, Feb 04 2012 *)

Extensions

More terms from Jason Kimberley, Feb 27 2012

A004592 Expansion of sqrt(10) in base 9.

Original entry on oeis.org

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

Views

Author

Keywords

Crossrefs

Cf. A010467.

Programs

  • Magma
    Prune(Reverse(IntegerToSequence(Isqrt(10*9^200),9))); // Jason Kimberley, Feb 19 2012
  • Mathematica
    RealDigits[Sqrt[10],9,100][[1]]  (* Harvey P. Dale, Mar 06 2011 *)

Extensions

Corrected and extended by Harvey P. Dale, Mar 06 2011
More terms from Jason Kimberley, Feb 27 2012

A059177 Engel expansion of sqrt(10) = 3.16227...

Original entry on oeis.org

1, 1, 1, 7, 8, 12, 20, 86, 94, 118, 160, 179, 287, 315, 22588, 49419, 66011, 80779, 651661, 1078390, 1093865, 4254100, 27153191, 108815387, 220864645, 798937058, 992296124, 2196903274, 17524412379, 22828187385
Offset: 1

Views

Author

Keywords

Comments

Cf. A006784 for definition of Engel expansion.

References

  • F. Engel, Entwicklung der Zahlen nach Stammbruechen, Verhandlungen der 52. Versammlung deutscher Philologen und Schulmaenner in Marburg, 1913, pp. 190-191.

Crossrefs

Cf. A010467.

Programs

  • Mathematica
    EngelExp[A_, n_] := Join[Array[1 &, Floor[A]], First@Transpose@
    NestList[{Ceiling[1/Expand[#[[1]] #[[2]] - 1]], Expand[#[[1]] #[[2]] - 1]/1} &, {Ceiling[1/(A - Floor[A])], (A - Floor[A])/1}, n - 1]];
    EngelExp[N[Sqrt[10], 7!], 10] (* modified by G. C. Greubel, Dec 26 2016 *)
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