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.

Showing 1-4 of 4 results.

A374772 Decimal expansion of the upper bound of the density of sphere packing in the Euclidean 3-space resulting from the dodecahedral conjecture.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 19 2024

Keywords

Comments

See A374753 for more information on the dodecahedral conjecture.
Also isoperimetric quotient (see A381671 for definition) of a regular dodecahedron. - Paolo Xausa, May 19 2025

Examples

			0.7546973993374058303916521059902293313424321921459...
		

Crossrefs

Cf. A374753 (dodecahedral conjecture), A374755 (strong dodecahedral conjecture), A374771, A374837, A374838.

Programs

  • Mathematica
    First[RealDigits[Pi*Sqrt[5 + Sqrt[5]]/(15*Sqrt[10]*(Sqrt[5] - 2)), 10, 100]]
  • PARI
    Pi*sqrt(5 + sqrt(5))/(15*sqrt(10)*(sqrt(5) - 2)) \\ Charles R Greathouse IV, Feb 07 2025

Formula

Equals (4/3)*Pi/A374753 = 10*A019699/A374753.
Equals Pi*sqrt(5 + sqrt(5))/(15*sqrt(10)*(sqrt(5) - 2)).
Equals 4*Pi/A374755.
Equals 36*Pi*A102769^2/(A131595^3). - Paolo Xausa, May 19 2025

A374753 Decimal expansion of the volume of a regular dodecahedron having unit inradius.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 19 2024

Keywords

Comments

The dodecahedral conjecture (proved in 1988 by Thomas C. Hales and Sean McLaughlin, see links) states that, in any packing of unit spheres in the Euclidean 3-space, every Voronoi cell has volume at least equal to this value.

Examples

			5.55029102851551026907043211366183924073759821288...
		

Crossrefs

Cf. A019699, A374755 (strong dodecahedral conjecture), A374772 (density).

Programs

  • Mathematica
    First[RealDigits[10*Sqrt[130 - 58*Sqrt[5]], 10, 100]]

Formula

Equals (4/3)*Pi/A374772 = 10*A019699/A374772.
Equals 10*sqrt(130 - 58*sqrt(5)).
Equals A374755/3.

A374837 Decimal expansion of Bezdek and Daróczy-Kiss's upper bound for the surface area density of a unit ball in any face cone of a Voronoi cell in an arbitrary packing of unit balls in the Euclidean 3-space.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 21 2024

Keywords

Comments

See Theorem 1.1 in Bezdek and Daróczy-Kiss (2005).
See A374772 for an improved bound.

Examples

			0.7783683851377739227957671666059435201971163186281...
		

Crossrefs

Cf. A374753 (dodecahedral conjecture), A374755 (strong dodecahedral conjecture), A374772, A374838.

Programs

  • Mathematica
    First[RealDigits[(30*ArcCos[Sqrt[3]/2*Sin[Pi/5]] - 9*Pi)/(5*Tan[Pi/5]), 10, 100]]

Formula

Equals (30*arccos((sqrt(3)/2)*sin(Pi/5)) - 9*Pi)/(5*tan(Pi/5)).
Equals 4*Pi/A374838.

A374838 Decimal expansion of Bezdek and Daróczy-Kiss's lower bound for the surface area of any Voronoi cell in an arbitrary packing of unit balls in the Euclidean 3-space.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 21 2024

Keywords

Comments

See Theorem 1.1 in Bezdek and Daróczy-Kiss (2005).
See A374755 for an improved bound (the strong dodecahedral conjecture).

Examples

			16.144502852765379806937602328092933543868922009780...
		

Crossrefs

Cf. A374753 (dodecahedral conjecture), A374755 (strong dodecahedral conjecture), A374772, A374837.

Programs

  • Mathematica
    First[RealDigits[20*Pi*Tan[Pi/5]/(30*ArcCos[Sqrt[3]/2*Sin[Pi/5]] - 9*Pi), 10, 100]]

Formula

Equals 20*Pi*tan(Pi/5)/(30*arccos(sqrt(3)/2*sin(Pi/5)) - 9*Pi).
Equals 4*Pi/A374837.
Showing 1-4 of 4 results.