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 61-70 of 89 results. Next

A339262 Decimal expansion of the conjecturally maximum possible volume of a polyhedron with 10 vertices inscribed in the unit sphere.

Original entry on oeis.org

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

Views

Author

Hugo Pfoertner, Dec 07 2020

Keywords

Comments

The polyhedron (see linked illustration) has vertices at the poles and two square rings of vertices rotated by Pi/4 against each other, with a polar angle of approx. +-62.89908285 degrees against the poles. The polyhedron is completely described by this angle and its order 16 symmetry. It would be desirable to know a closed formula representation of this angle and the volume.

Examples

			2.218711131545399403247282751128417013810725374663344381750049084201...
		

Crossrefs

Cf. A010527 (volume of double 5-pyramid), A081314, A081366, A122553 (volume of octahedron), A339259, A339260, A339261, A339263.

A377750 Decimal expansion of the surface area of a truncated icosahedron with unit edge length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Nov 06 2024

Keywords

Examples

			72.60725303413392187893153397383948620117264765443...
		

Crossrefs

Cf. A377751 (volume), A377752 (circumradius), A205769 (midradius + 1), A377787 (Dehn invariant).
Cf. A010527 (analogous for a regular icosahedron, with offset 1).

Programs

  • Mathematica
    First[RealDigits[3*(10*Sqrt[3] + Sqrt[25 + Sqrt[500]]), 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["TruncatedIcosahedron", "SurfaceArea"], 10, 100]]
  • PARI
    3*(10*sqrt(3) + sqrt(25 + 10*sqrt(5))) \\ Charles R Greathouse IV, Feb 05 2025

Formula

Equals 3*(10*sqrt(3) + sqrt(25 + 10*sqrt(5))) = 30*A002194 + 3*sqrt(25 + 10*A002163).
Equals 30*(A002194 + A375067).

A386412 Decimal expansion of the surface area of an augmented truncated tetrahedron with unit edge.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 21 2025

Keywords

Comments

The augmented truncated tetrahedron is Johnson solid J_65.

Examples

			14.258330249197702407928401219788170385128234149767...
		

Crossrefs

Cf. A386411 (volume).
Cf. A010527.

Programs

  • Mathematica
    First[RealDigits[3 + 13*Sqrt[3]/2, 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["J65", "SurfaceArea"], 10, 100]]

Formula

Equals 3 + 13*sqrt(3)/2 = 3 + 13*A010527.
Equals the largest root of 4*x^2 - 24*x - 471.

A126664 Continued fraction expansion of sqrt(3)/2.

Original entry on oeis.org

0, 1, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6, 2, 6
Offset: 0

Views

Author

Zerinvary Lajos, Feb 10 2007

Keywords

Comments

Also continued fraction expansion of sin(Pi/3).

Crossrefs

Cf. A010527.

Programs

  • Mathematica
    ContinuedFraction[Sqrt[3]/2,120] (* or *) PadRight[{0,1},120,{6,2}] (* Harvey P. Dale, May 14 2016 *)

Formula

a(n) = 2*(2+(-1)^n) for n>1. a(n) = a(n-2) for n>3. G.f.: -x*(x^2+6*x+1) / ((x-1)*(x+1)). - Colin Barker, Jan 10 2014

Extensions

More terms from N. J. A. Sloane, Dec 29 2008

A152422 Decimal expansion of (sqrt(3)-1)/2.

Original entry on oeis.org

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

Views

Author

Geoffrey Caveney, Dec 03 2008

Keywords

Comments

The number has continued fraction [0, 2, 1, 2, 1, 2, 1, ...].
The iterated function z^2 - 1/2 gives a good rational approximation of this number times -1 after sixty steps. - Alonso del Arte, Apr 10 2016

Examples

			0.36602540378443864676372317...
		

Crossrefs

A variant of A010527, which is the main entry. - N. J. A. Sloane, Dec 04 2008

Programs

Formula

Equals Product_{k>=1} (1 + (-1)^k * 2/(6*k-3)). - Amiram Eldar, Aug 10 2020

Extensions

a(98) corrected by Georg Fischer, Apr 03 2020

A179639 Decimal expansion of the volume of gyroelongated pentagonal pyramid with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Gyroelongated pentagonal pyramid: 11 vertices,25 edges,and 16 faces.

Examples

			1.88019215822908780282010679244089525495689855152098881326825313369561...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[(25+9*Sqrt[5])/24,200]]

Formula

Digits of (25+9*sqrt(5))/24.

A179640 Decimal expansion of the surface area of gyroelongated pentagonal pyramid with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Gyroelongated pentagonal pyramid: 11 vertices, 25 edges, and 16 faces.

Examples

			8.21566792897225677348693575803563097544289387179912568441637087996861...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[Sqrt[5/2*(70+Sqrt[5]+3*Sqrt[75+30*Sqrt[5]])]/2,200]]

Formula

Digits of sqrt(5/2*(70+sqrt(5)+3*sqrt(75+30*sqrt(5))))/2.

A179641 Decimal expansion of the volume of pentagonal dipyramid with edge length 1.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Pentagonal dipyramid: 7 vertices, 15 edges, and 10 faces.

Examples

			0.60300566479164914136743113906093968628671819663429381035590810378421...
		

Crossrefs

Programs

Formula

Digits of (5+sqrt(5))/12.

Extensions

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

A339263 Decimal expansion of the conjecturally maximum possible volume of a polyhedron with 11 vertices inscribed in the unit sphere.

Original entry on oeis.org

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

Views

Author

Hugo Pfoertner, Dec 07 2020

Keywords

Comments

The polyhedron (see linked illustration) with a symmetry group of order 4 has a vertex in the north pole on its axis of symmetry. The remaining 10 vertices are diametrically opposite in pairs relative to this axis of symmetry. The polar vertex has vertex degree 6. 8 vertices have vertex degree 5. 2 vertices have vertex degree 4.
This allocation seems to be the best possible approximation of a medial distribution of the vertex degrees, which is a known necessary condition for maximum volume. Of the 25 possible triangulations with vertex degree >= 4, all the others have more than 2 vertices with vertex degree 4, which leads to more pointed corners and therefore smaller volumes.

Examples

			2.35463449506861520323688059263892654160344864269342168599607566...
		

Crossrefs

Cf. A010527 (volume of double 5-pyramid), A081314, A081366, A122553 (volume of octahedron), A339259, A339260, A339261, A339262.

A377346 Decimal expansion of the midradius of a truncated cuboctahedron (great rhombicuboctahedron) with unit edge length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Oct 26 2024

Keywords

Examples

			2.26303343845371462359202580343253714222906720265...
		

Crossrefs

Cf. A377343 (surface area), A377344 (volume), A377345 (circumradius).
Cf. A010527 (analogous for a cuboctahedron).

Programs

  • Mathematica
    First[RealDigits[Sqrt[3 + 3/Sqrt[2]], 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["TruncatedCuboctahedron", "Midradius"], 10, 100]]

Formula

Equals sqrt(12 + 6*sqrt(2))/2 = sqrt(12 + A010524)/2 = sqrt(3 + 3/sqrt(2)) = sqrt(3 + A230981).
Previous Showing 61-70 of 89 results. Next