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 11-20 of 30 results. Next

A179590 Decimal expansion of the volume of pentagonal cupola with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Pentagonal cupola: 15 vertices, 25 edges, and 12 faces.

Examples

			2.32404531833319313093944911248751749029374557307435048284726483027368...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[(5+4*Sqrt[5])/6,200]]

Formula

Digits of (5+4*sqrt(5))/6.

A179553 Decimal expansion of the surface area of pentagonal pyramid with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Pentagonal pyramid: 6 faces, 6 vertices, and 10 edges.

Examples

			3.885540910050063539668319904270950058085880737273174114276853431338785...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[Sqrt[5/2*(10+Sqrt[5]+Sqrt[75+30*Sqrt[5]])]/2,200]]

Formula

Digits of sqrt(5/2*(10+sqrt(5)+sqrt(75+30sqrt(5))))/2.

A121570 Decimal expansion of cosecant of 36 degrees = csc(Pi/5) = 1/sin(Pi/5).

Original entry on oeis.org

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

Views

Author

Rick L. Shepherd, Aug 08 2006

Keywords

Comments

1 + csc(Pi/5) is the radius of the smallest circle into which 5 unit circles can be packed ("r=2.701+ Proved by Graham in 1968.", according to the Friedman link, which has a diagram).
csc(Pi/5) = 1/A019845 is the distance between the center of the larger circle and the center of each unit circle.
The problem of finding the diameter d of the circumscribing circle of a regular pentagon of side s = 10 (in some length units) appears as an example in Abū Kāmil's treatise on the pentagon and decagon (see the Havil reference) and Abū Kāmil links. The answer is d/s = 1/sin(Pi/5). - Wolfdieter Lang, Mar 01 2018
Longer diagonal of golden rhombus with unit edge length. - Eric W. Weisstein, Dec 11 2018
The length of the longer side of a golden rectangle inscribed in a unit circle. - Michal Paulovic, Sep 01 2022
The radius of a common circle surrounded by 5 tangent unit circles is A121570 - 1. - Thomas Otten, Dec 27 2023

Examples

			1.701301616704079864363080994126...
		

References

  • Julian Havil, The Irrationals, Princeton University Press, Princeton and Oxford, 2012, pp. 58.

Crossrefs

Cf. A001622, A019845 (inverse), A182007 (2/A121570).
Cf. A179290 (shorter golden rhombus diagonal).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:= RealField(); 1/Sin(Pi(R)/5); // G. C. Greubel, Nov 02 2018
    
  • Maple
    evalf(1/sin(Pi/5),130); # Muniru A Asiru, Nov 02 2018
  • Mathematica
    RealDigits[Csc[Pi/5], 10, 100][[1]] (* G. C. Greubel, Nov 02 2018 *)
  • PARI
    1/sin(Pi/5)
    
  • Sage
    numerical_approx(1/sin(pi/5), digits=100) # G. C. Greubel, Dec 12 2018

Formula

Equals 1/A019845.
Equals 2*(2*phi - 1)*sqrt(2 + phi)/5, with the golden ratio phi = A001622. - Wolfdieter Lang, Mar 01 2018
Equals sqrt(2 + 2 / sqrt(5)). - Michal Paulovic, Sep 01 2022
The minimal polynomial is 5*x^4 - 20*x^2 + 16. - Joerg Arndt, Sep 09 2022

A179296 Decimal expansion of circumradius of a regular dodecahedron with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Dodecahedron: A three-dimensional figure with 12 faces, 20 vertices, and 30 edges.
Appears as a coordinate in a degree-7 quadrature formula on 12 points over the unit circle [Stroud & Secrest]. - R. J. Mathar, Oct 12 2011

Examples

			1.40125853844407354467667793532206799444393173977549286366084518639135...
		

References

  • Jan Gullberg, Mathematics from the Birth of Numbers, W. W. Norton & Co., NY & London, 1997, §12.4 Theorems and Formulas (Solid Geometry), p. 451.

Crossrefs

Cf. Platonic solids circumradii: A010503 (octahedron), A010527 (cube), A019881 (icosahedron), A187110 (tetrahedron). - Stanislav Sykora, Feb 10 2014

Programs

  • Mathematica
    RealDigits[(Sqrt[3]+Sqrt[15])/4, 10, 175][[1]]
  • PARI
    (1+sqrt(5))*sqrt(3)/4 \\ Stefano Spezia, Jan 27 2025

Formula

Equals (sqrt(3) + sqrt(15))/4 = sqrt((9 + 3*sqrt(5))/8).
The minimal polynomial is 16*x^4 - 36*x^2 + 9. - Joerg Arndt, Feb 05 2014
Equals (sqrt(3)/2) * phi = A010527 * A001622. - Amiram Eldar, Jun 02 2023

A179591 Decimal expansion of the surface area of pentagonal cupola with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Pentagonal cupola: 15 vertices, 25 edges, and 12 faces.

Examples

			16.5797497529881970460940463443632246181026360961176551818747440...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[(20+Sqrt[10*(80+31*Sqrt[5]+Sqrt[2175+930*Sqrt[5]])])/4,200]]

Formula

Digits of (20+sqrt(10*(80+31*sqrt(5)+sqrt(2175+930*sqrt(5)))))/4.

A179588 Decimal expansion of the surface area of square cupola with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Square cupola: 12 vertices, 20 edges, and 10 faces.

Examples

			11.56047793231506739113082378992526852408214900456427677440...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[7+2*Sqrt[2]+Sqrt[3],200]]

Formula

Digits of 7 + 2*sqrt(2) + sqrt(3).

A179637 Decimal expansion of the surface area of pentagonal rotunda with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Pentagonal rotunda: 20 vertices, 35 edges, and 17 faces.

Examples

			22.3472002653941282767984141581886130738180135134316226129799763167102...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[Sqrt[5*(145+58*Sqrt[5]+2*Sqrt[30*(65+29*Sqrt[5])])]/2,200]]

Formula

Digits of sqrt(5*(145+58*sqrt(5)+2*sqrt(30*(65+29*sqrt(5)))))/2.

Extensions

Offset corrected by R. J. Mathar, Aug 15 2010

A185093 Decimal expansion of the volume of small rhombicosidodecahedron with edge = 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Small Rhombicosidodecahedron: 62 faces, 60 vertices, and 120 edges.
Surface Area = 30+sqrt(30*(10+3*sqrt(5)+sqrt(75+30*sqrt(5)))) = 59.30598284491...
Circumradius = sqrt(11+4*sqrt(5))/2 = 2.23295050941569004950041538324968277293...
Midradius = sqrt(10+4*sqrt(5))/2 = 2.17625089948282151110005286599776788019807...
Quadratic number with denominator 3 and minimal polynomial 9x^2 - 360x - 605. - Charles R Greathouse IV, Apr 25 2016

Examples

			41.6153237824979670652886787977356702759259774762447486679520...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[20 + (29*Sqrt[5])/3, 200]][[1]]
    RealDigits[PolyhedronData["Rhombicosidodecahedron","Volume"],10,100][[1]] (* Harvey P. Dale, Aug 04 2025 *)
  • PARI
    29*sqrt(5)/3+20 \\ Charles R Greathouse IV, Oct 01 2012

Extensions

Offset changed by Georg Fischer, Jul 29 2021

A179589 Decimal expansion of the circumradius of square cupola with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Square cupola: 12 vertices, 20 edges, and 10 faces.

Examples

			1.398966325965906702031540539431998764673522563866238879930...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[Sqrt[5+2*Sqrt[2]]/2,200]]

Formula

Digits of sqrt(5+2*sqrt(2))/2.

A179638 Decimal expansion of the volume of gyroelongated square pyramid with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Gyroelongated square pyramid: 9 vertices, 20 edges, and 13 faces.

Examples

			1.19270224223223255906019842837725158155262551828862015707793142188822...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[(Sqrt[2]+2*Sqrt[4+3*Sqrt[2]])/6,200]]

Formula

Digits of (sqrt(2)+2 sqrt(4+3 sqrt(2)))/6.
Previous Showing 11-20 of 30 results. Next