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.

Previous Showing 11-15 of 15 results.

A088543 Decimal expansion of sqrt(15)/2.

Original entry on oeis.org

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

Views

Author

Christopher M. Tomaszewski (cmt1288(AT)comcast.net), Nov 16 2003

Keywords

Comments

This is the ratio of the base of an isosceles triangle to its height when the other two sides are each equal to twice the base.
Exradius opposite the side of length 3 of the obtuse scalene triangle with sides of lengths 2, 3 and 4, the scalene triangle with least integer side lengths. See formulas in the Weisstein link. - Rick L. Shepherd, May 14 2008

Examples

			1.93649167310370844258963269989119980541646085264579541329378688305674154596...

Links

Crossrefs

Cf. A010527.
Cf. A140239, A140246, A140247, A140248, A140249, A010472.

Programs

  • Mathematica
    First[RealDigits[Sqrt[15]/2, 10, 100]] (* Paolo Xausa, Jun 18 2024 *)

Formula

sqrt(15)/2 = A010472/2 = A140249/3. - Rick L. Shepherd, May 14 2008

Extensions

More terms from Rick L. Shepherd, May 14 2008

A140272 Decimal expansion of arctan(3*sqrt(15)/29).

Original entry on oeis.org

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

Views

Author

Rick L. Shepherd, May 16 2008, Jul 18 2008

Keywords

Comments

The Brocard angle in radians of the obtuse scalene triangle with sides of lengths 2, 3 and 4, the scalene triangle with least integer side lengths. See formulas in the Weisstein link.

Examples

			0.38106956877756026908149342379874213938224647938776469222831569013225470496...

Links

Crossrefs

Cf. A140273, A140239.

Programs

  • Mathematica
    RealDigits[ArcTan[(3Sqrt[15])/29],10,120][[1]] (* Harvey P. Dale, Aug 24 2019 *)
  • PARI
    atan(3*sqrt(15)/29)

Formula

arctan(3*sqrt(15)/29) = arctan(4*A140239/29) = arcsin(3*sqrt(915)/244) = arccos(29*sqrt(61)/244).

A140273 Decimal expansion of 180*arctan(3*sqrt(15)/29)/Pi.

Original entry on oeis.org

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

Views

Author

Rick L. Shepherd, May 16 2008

Keywords

Comments

The Brocard angle in degrees of the obtuse scalene triangle with sides of lengths 2, 3 and 4, the scalene triangle with least integer side lengths. See formulas in the Weisstein link.

Examples

			21.8336779918244521003850617600545717959829354103823836061588021960485224460...

Links

Crossrefs

Cf. A140272, A140239.

Programs

  • Mathematica
    RealDigits[180 ArcTan[(3Sqrt[15])/29]/Pi,10,120][[1]] (* Harvey P. Dale, Dec 15 2012 *)
  • PARI
    180*atan(3*sqrt(15)/29)/Pi

Formula

180*arctan(3*sqrt(15)/29)/Pi = 180*A140272/Pi = 180*arctan(4*A140239/29)/Pi.

A179021 Decimal expansion of sqrt(231)/4.

Original entry on oeis.org

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

Views

Author

Vladimir Joseph Stephan Orlovsky, Jun 25 2010

Keywords

Comments

Area of the obtuse scalene triangle with sides of lengths 2, 4 and 5. Second smallest area of triangle with distinct integer sides.

Examples

			3.79967103839266590791718605150991125939558161542555907919914059630091...

Crossrefs

Cf. A140239.

Programs

  • Mathematica
    a=2;b=4;c=5;s=(a+b+c)/2;area=Sqrt[s*(s-a)*(s-b)*(s-c)];RealDigits[N[area,200]]
RealDigits[Sqrt[231]/4,10,120][[1]] (* Harvey P. Dale, Apr 08 2018 *)

A179022 Decimal expansion of 3*sqrt(39)/4.

Original entry on oeis.org

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

Views

Author

Vladimir Joseph Stephan Orlovsky, Jun 25 2010

Keywords

Comments

Area of the obtuse scalene triangle with sides of lengths 2, 5 and 6. 3rd smallest area of triangle with distinct integer sides.

Crossrefs

Cf. A140239, A179021.

Programs

  • Mathematica
    a=2;b=5;c=6;s=(a+b+c)/2;area=Sqrt[s*(s-a)*(s-b)*(s-c)];RealDigits[N[area,200]]
  • PARI
    sqrt(351)/4 \\ Charles R Greathouse IV, Apr 25 2016
Previous Showing 11-15 of 15 results.

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