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 20 results.

A386460 Decimal expansion of the surface area of an augmented truncated cube with unit edges.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 23 2025

Keywords

Comments

The augmented truncated cube is Johnson solid J_66.

Examples

			34.33828804643758236859922626661459788652513451520...
		

Crossrefs

Cf. A386459 (volume).

Programs

  • Mathematica
    First[RealDigits[15 + Sqrt[200] + Sqrt[27], 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["J66", "SurfaceArea"], 10, 100]]

Formula

Equals 15 + 10*sqrt(2) + 3*sqrt(3) = 15 + 10*A002193 + A010482.
Equals the largest root of x^4 - 60*x^3 + 896*x^2 + 120*x - 21596.

A041042 Numerators of continued fraction convergents to sqrt(27).

Original entry on oeis.org

5, 26, 265, 1351, 13775, 70226, 716035, 3650401, 37220045, 189750626, 1934726305, 9863382151, 100568547815, 512706121226, 5227629760075, 26650854921601, 271736178976085, 1385331749802026, 14125053676996345
Offset: 0

Views

Author

Keywords

Comments

Subset of |A002316| (conjectured).

Crossrefs

Programs

  • Mathematica
    Table[Numerator[FromContinuedFraction[ContinuedFraction[Sqrt[27],n]]],{n,1,50}] (* Vladimir Joseph Stephan Orlovsky, Mar 18 2011*)
    Numerator/@Convergents[Sqrt[27],20] (* Harvey P. Dale, Jul 21 2011 *)
    CoefficientList[Series[(- x^3 + 5 x^2 + 26 x + 5)/(x^4 - 52 x^2 + 1), {x, 0, 30}], x]  (* Vincenzo Librandi, Oct 28 2013 *)
    a0[n_] := (-5-3*Sqrt[3]+(-5+3*Sqrt[3])*(26+15*Sqrt[3])^(2*n))/(2*(26+15*Sqrt[3])^n) // Simplify
    a1[n_] := (1+(26+15*Sqrt[3])^(2*n))/(2*(26+15*Sqrt[3])^n) //  Simplify
    Flatten[MapIndexed[{a0[#], a1[#]}&,Range[10]]] (* Gerry Martens, Jul 10 2015 *)
    LinearRecurrence[{0,52,0,-1},{5,26,265,1351},30] (* Harvey P. Dale, Dec 12 2015 *)

Formula

G.f.: (-x^3+5x^2+26x+5)/(x^4-52x^2+1).
From Gerry Martens, Jul 11 2015: (Start)
Interspersion of 2 sequences [a0(n),a1(n)]:
a0(n) = ((-5-3*sqrt(3))/(26+15*sqrt(3))^n+(-5+3*sqrt(3))*(26+15*sqrt(3))^n)/2.
a1(n) = (1/(26+15*sqrt(3))^n+(26+15*sqrt(3))^n)/2. (End)

A374948 Decimal expansion of the Euclidean length of the minimum Steiner tree joining all the vertices of a unit cube.

Original entry on oeis.org

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

Views

Author

Marco RipĂ , Jul 24 2024

Keywords

Comments

The 1994 Bridge's paper entitled "Minimal Steiner Trees for Three Dimensional Networks" (see Links) suggested an optimal strategy to solve the minimum Steiner tree problem for the unit cube {0,1}^3, and the total length of the provided Steiner Tree is 1 + 3*sqrt(3).
Also the surface area of a gyroelongated square pyramid (Johnson solid J_10) with unit edges. - Paolo Xausa, Aug 04 2025

Examples

			6.1961524227066318805823390245176171008284157614311418841674209383...
		

Crossrefs

Essentially the same as A178809, A176532 and A010482.

Programs

  • Mathematica
    RealDigits[3Sqrt[3]+1,10,87][[1]] (* Stefano Spezia, Jul 25 2024 *)

Formula

Equals 3*sqrt(3) + 1.
Equals A010482(n) for any n >= 2 and a(1) = A010482(1) + 1.

A386739 Decimal expansion of the volume of a sphenocorona with unit edges.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Aug 01 2025

Keywords

Comments

The sphenocorona is Johnson solid J_86.

Examples

			1.5153516399764065597284793124718129048228695068...
		

Crossrefs

Cf. A010482 (surface area - 2), A178809 (surface area + 4).

Programs

  • Mathematica
    First[RealDigits[Sqrt[1 + 3*Sqrt[3/2] + Sqrt[13 + Sqrt[54]]]/2, 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["J86", "Volume"], 10, 100]]

Formula

Equals sqrt(1 + 3*sqrt(3/2) + sqrt(13 + 3*sqrt(6)))/2 = sqrt(1 + 3*A115754 + sqrt(13 + A010507))/2.
Equals A386740 - A020775.
Equals the largest real root of 1024*x^8 - 1024*x^6 - 3008*x^4 - 96*x^2 + 9.

A176532 Decimal expansion of 5+3*sqrt(3).

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 24 2010

Keywords

Comments

Continued fraction expansion of 5+3*sqrt(3) is A010721 preceded by 10.
a(n) = A010482(n-2) for n > 3.

Examples

			5+3*sqrt(3) = 10.19615242270663188058...
		

Crossrefs

Cf. A002194 (decimal expansion of sqrt(3)), A010482 (decimal expansion of sqrt(27)), A010721 (repeat 5, 10).

Programs

  • Mathematica
    RealDigits[5+3Sqrt[3],10,120][[1]] (* Harvey P. Dale, May 30 2012 *)

A386695 Decimal expansion of the volume of a snub disphenoid with unit edges.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 31 2025

Keywords

Comments

The snub disphenoid is Johnson solid J_84.

Examples

			0.85949364619130053155540963697973639270749722...
		

Crossrefs

Cf. A010482 (surface area).
Cf. A386696.

Programs

  • Mathematica
    First[RealDigits[Root[5832*#^6 - 1377*#^4 - 2160*#^2 - 4 &, 2], 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["J84", "Volume"], 10, 100]]

Formula

Equals the largest real root of 5832*x^6 - 1377*x^4 - 2160*x^2 - 4.

A171542 Decimal expansion of sqrt(27/70).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Dec 11 2009

Keywords

Comments

The absolute value of the Clebsch-Gordan coupling coefficient = <2 3/2 ; -1 3/2 | 5/2 1/2>.

Examples

			sqrt(27/70) = 3*sqrt(210)/70 = 0.621059003408118796016514178164...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Sqrt[27/70],10,120][[1]] (* Harvey P. Dale, Apr 26 2011 *)

Formula

A370562 Decimal expansion of (2*Pi - 3*sqrt(3))/2.

Original entry on oeis.org

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

Views

Author

Wolfdieter Lang, Mar 15 2024

Keywords

Comments

This constant is the difference of the area of a disk with radius 1 (length unit) and the inscribed regular hexagon.

Examples

			0.5435164422364772981714738710206943337829615186595348788912...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Pi - 3*Sqrt[3]/2, 10, 120][[1]] (* Amiram Eldar, Mar 15 2024 *)

Formula

Equals (A019692 - A010482)/2.
Equals Pi - 3*sqrt(3)/2 = A000796 - A104956.

A375741 Decimal expansion of 6*Pi/(3*sqrt(3) + 8*Pi).

Original entry on oeis.org

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

Views

Author

Stefano Spezia, Aug 26 2024

Keywords

Comments

This constant expresses the expected proportion of individuals that belong to reciprocal nearest-neighbor relationship pairs in a population of random patterns over a plane.

Examples

			0.62150489688743159140596781880802827312707885...
		

References

  • E. C. Pielou, An Introduction to Mathematical Ecology, John Wiley & Sons, Inc. 1969. See pp. 121-122.

Crossrefs

Programs

  • Mathematica
    RealDigits[6Pi/(3Sqrt[3]+8Pi),10,100][[1]]

Formula

Equals Integral_{x=0..oo} 2*Pi*x*exp(-x^2*(sqrt(3)/2+4*Pi/3)) dx. [Pielou, 1969]

A379392 Decimal expansion of 3*sqrt(3)/(4*Pi^2).

Original entry on oeis.org

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

Views

Author

Stefano Spezia, Dec 22 2024

Keywords

Examples

			0.13162007846365924284255259402723358616623004162...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 8.4.2, p. 494.

Crossrefs

Programs

  • Mathematica
    RealDigits[3Sqrt[3]/(4Pi^2),10,100][[1]]

Formula

Equals A240935/Pi. - Hugo Pfoertner, Dec 22 2024
Previous Showing 11-20 of 20 results.