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 1-5 of 5 results.

A381684 Decimal expansion of the isoperimetric quotient of a truncated tetrahedron.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Mar 04 2025

Keywords

Comments

Polya (1954) defines the isoperimetric quotient of a solid as 36*Pi*V^2/S^3, where V and S are the volume and surface area of the solid, respectively.
The isoperimetric quotient of a sphere is 1.

Examples

			0.4662292826432950646084875599089894958106273300491...
		

References

  • George Polya, Mathematics and Plausible Reasoning, Vol. 1: Induction and Analogy in Mathematics, Princeton University Press, Princeton, New Jersey, 1954. See pp. 188-189, exercise 43.

Crossrefs

Cf. A377274 (surface area), A377275 (volume).

Programs

  • Mathematica
    First[RealDigits[529*Pi/(2058*Sqrt[3]), 10, 100]]
  • PARI
    529*Pi/2058/sqrt(3) \\ Charles R Greathouse IV, Aug 19 2025

Formula

Equals 36*Pi*A377275^2/(A377274^3).
Equals 529*Pi/(2058*sqrt(3)) = 529*A000796/(2058*A002194).

A378204 Decimal expansion of the surface area of a triakis tetrahedron with unit shorter edge length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Nov 20 2024

Keywords

Comments

The triakis tetrahedron is the dual polyhedron of the truncated tetrahedron.

Examples

			5.5277079839256664151915545611178111398784809093...
		

Crossrefs

Cf. A378205 (volume), A378206 (inradius), A378207 (midradius), A378208 (dihedral angle).
Cf. A377274 (surface area of a truncated tetrahedron with unit edge).
Cf. A010468.

Programs

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

Formula

Equals (5/3)*sqrt(11) = (5/3)*A010468.

A377275 Decimal expansion of the volume of a truncated tetrahedron with unit edge length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Oct 23 2024

Keywords

Examples

			2.7105759945484321768699033880685879839252044278...
		

Crossrefs

Cf. A377274 (surface area), A377276 (circumradius), A093577 (midradius), A377277 (Dehn invariant).
Cf. A020829 (analogous for a regular tetrahedron).
Cf. A002193.

Programs

  • Mathematica
    First[RealDigits[23/12*Sqrt[2], 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["TruncatedTetrahedron", "Volume"], 10, 100]]

Formula

Equals (23/12)*sqrt(2) = (23/12)*A002193.

A377276 Decimal expansion of the circumradius of a truncated tetrahedron with unit edge length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Oct 23 2024

Keywords

Examples

			1.17260393995585738864140752838611657014705708835...
		

Crossrefs

Cf. A377274 (surface area), A377275 (volume), A093577 (midradius), A377277 (Dehn invariant).
Cf. A187110 (analogous for a regular tetrahedron).
Cf. A010478.

Programs

  • Mathematica
    First[RealDigits[Sqrt[22]/4, 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["TruncatedTetrahedron", "Circumradius"], 10, 100]]

Formula

Equals sqrt(22)/4 = A010478/4.

A379732 Decimal expansion of 207/208.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Dec 31 2024

Keywords

Comments

Conjectured densest packing of truncated tetrahedra.

Examples

			0.995192307692307692307692307692307692307692307692...
		

Crossrefs

Programs

  • Mathematica
    First[RealDigits[207/208, 10, 100]]
Showing 1-5 of 5 results.