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 11-16 of 16 results.

A386691 Decimal expansion of the volume of a parabidiminished rhombicosidodecahedron with unit edges.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 30 2025

Keywords

Comments

The parabidiminished rhombicosidodecahedron is Johnson solid J_80.
Also the volume of a metabidiminished rhombicosidodecahedron and a gyrate bidiminished rhombicosidodecahedron (Johnson solids J_81 and J_82, respectively) with unit edges.

Examples

			36.967233145831580803409780572760635295338486330...
		

Crossrefs

Cf. A386692 (surface area).

Programs

  • Mathematica
    First[RealDigits[5/3*(11 + 5*Sqrt[5]), 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["J80", "Volume"], 10, 100]]

Formula

Equals (5/3)*(11 + 5*sqrt(5)) = (5/3)*(11 + 5*A002163).
Equals A185093 - 2*A179590.
Equals (50/3)*A001622 + 10 = A134946*100 + 10.
Equals the largest root of 9*x^2 - 330*x - 100.

A386693 Decimal expansion of the volume of a tridiminished rhombicosidodecahedron with unit edges.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 31 2025

Keywords

Comments

The tridiminished rhombicosidodecahedron is Johnson solid J_83.

Examples

			34.64318782749838767247033146027311780504474075702...
		

Crossrefs

Cf. A386694 (surface area).

Programs

  • Mathematica
    First[RealDigits[35/2 + 23/3*Sqrt[5], 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["J83", "Volume"], 10, 100]]

Formula

Equals 35/2 + (23/3)*sqrt(5) = 35/2 + (23/3)*A002163.
Equals A185093 - 3*A179590.
Equals the largest root of 36*x^2 - 1260*x + 445.

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

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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.

A386852 Decimal expansion of the dihedral angle, in radians, between the pentagonal face and a triangular face in a pentagonal pyramid with equal edges (Johnson solid J_2).

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Aug 05 2025

Keywords

Comments

Also the dihedral angle, in radians, between the 10-gonal face and a triangular face in a pentagonal cupola (Johnson solid J_5)

Examples

			0.65235813978436818599539063164382257436530791996...
		

Crossrefs

Cf. A179552 (J_2 volume), A179553 (J_2 surface area).
Cf. A179590 (J_5 volume), A179591 (J_5 surface area).

Programs

  • Mathematica
    First[RealDigits[ArcSec[Sqrt[15 - 6*Sqrt[5]]], 10, 100]] (* or *)
    First[RealDigits[Min[PolyhedronData["J2", "DihedralAngles"]], 10, 100]]
  • PARI
    acos(sqrt((5+2*sqrt(5))/15)) \\ Charles R Greathouse IV, Aug 19 2025

Formula

Equals arcsec(sqrt(15 - 6*sqrt(5))) = arcsec(sqrt(15 - 6*A002163)).
Equals arccos(sqrt((5 + 2*sqrt(5))/15)) = arccos(sqrt((5 + A010476)/15)).

A334114 Decimal expansion of volume of a sphenomegacorona (J88) with each edge of unit length.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

A sphenomegacorona is one of the 92 regular-faced non-isogonal convex polyhedra first enumerated by Norman W. Johnson. It's built out of 2 squares and 12 equilateral triangles.
This number is algebraic, of unknown degree.
It appears that the minimal polynomial is 521578814501447328359509917696*x^32 - 985204427391622731345740955648*x^30 - 16645447351681991898880656015360*x^28 + 79710816694053483249372512649216*x^26 - 152195045391070538203422101864448*x^24 + 156280253448056209478031589244928*x^22 - 96188116617075838858708654227456*x^20 + 30636368373570166303441645731840*x^18 + 5828527077458909552923002273792*x^16 - 8060049780765551057159394951168*x^14 + 1018074792115156107372011716608*x^12 + 35220131544370794950945931264*x^10 + 327511698517355918956755959808*x^8 - 116978732884218191486738706432*x^6 + 10231563774949176791703149568*x^4 - 366323949299263261553952192*x^2 + 3071435678740442112675625. - Joerg Arndt, Apr 16 2020

Examples

			1.94810822885947280327067639...
		

Crossrefs

Volumes of other Johnson solids: A179552, A179587, A179590.

Programs

  • Mathematica
    k := Root[-23 - 56 x + 200 x^2 + 304 x^3 - 776 x^4 + 240 x^5 +
       2000 x^6 - 5584 x^7 - 3384 x^8 + 17248 x^9 + 2464 x^10 -
       24576 x^11 + 1568 x^12 + 17216 x^13 - 3712 x^14 - 4800 x^15 +
       1680 x^16, 2];
    {{0, 1/2, Sqrt[1 - k^2]}, {k, 1/2, 0}, {0, Sqrt[(3/4 - k^2)/(1 - k^2)] + 1/2, (1/2 - k^2)/Sqrt[1 - k^2]}, {1/2, 0, -Sqrt[1/2 + k - k^2]}, {0, (Sqrt[3/4 - k^2] (2 k^2 - 1))/((k^2 - 1) Sqrt[1 - k^2]) + 1/2, (k^4 - 1/2)/(1 - k^2)^(3/2)}};
    v = Union[%, {1, -1, 1}*# & /@ %, {-1, 1, 1}*# & /@ %, {-1, -1,
      1}*# & /@ %];
    f := {{2, 3, 12, 11}, {2, 3, 10, 9}, {3, 12, 5}, {3, 10, 5}, {12, 5,
      7}, {10, 5, 7}, {7, 12, 8}, {7, 10, 1}, {12, 8, 11}, {10, 1,
      9}, {8, 1, 7}, {8, 1, 6}, {8, 11, 6}, {1, 9, 6}, {11, 6, 4}, {9,
      6, 4}, {4, 11, 2}, {4, 9, 2}};
    RealDigits[N[Volume[Polyhedron[v, f]], 20000]][[1]]
Previous Showing 11-16 of 16 results.