A363437 -id:A363437 - cp's OEIS frontend

A122553 a(0)=1, a(n)=3 for n > 0.

1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3

Offset: 0

Philippe Deléham, Sep 20 2006

Continued fraction for (sqrt(13) - 1)/2 = A223139.
Decimal expansion of 4/30. - Alonso del Arte, Aug 16 2012
4/3 is the volume of the regular octahedron inscribed in the unit-radius sphere. - Amiram Eldar, Jun 02 2023

Calvin C. Clawson, Mathematical Mysteries, The Beauty and Magic of Numbers, Springer, 2013, pp. 95-96, 224.

Jun Yan, Results on pattern avoidance in parking functions, arXiv:2404.07958 [math.CO], 2024. See p. 4.
Index entries for linear recurrences with constant coefficients, signature (1).

Cf. A118273 (cube), A339259 (regular icosahedron), A363437 (regular tetrahedron), A363438 (regular dodecahedron).

Cf. A223139.

RealDigits[4/3, 10, 105][[1]] (* Alonso del Arte, Aug 16 2012 *)
PadRight[{1},120,3] (* Harvey P. Dale, Jul 21 2023 *)

a(n)=(n>=0)+2*(n>0) \\ Jaume Oliver Lafont, Mar 26 2009

a(n) = 3 - 2*0^n.
G.f.: (1 + 2*x)/(1 - x).
Sum_{n >= 0} a(n)*10^(-n) = 4/3.
From Amiram Eldar, Jun 05 2021: (Start)
4/3 = Product_{k>=1} (1 + 1/2^(2^k)).
4/3 = Sum_{k>=0} binomial(2*k,k)/((k+2)*4^k). (End)
Sum_{k>0} 3*k/4^k = 4/3 [Nicole Oresme]. - Stefano Spezia, Jun 27 2024
K_{n>=3} n/(n-2) = 4/3 (see Clawson at p. 224). - Stefano Spezia, Jul 01 2024
E.g.f.: 3*exp(x) - 2. - Elmo R. Oliveira, Aug 05 2024

A339259 Decimal expansion of the volume of the regular icosahedron inscribed in the unit sphere.

Original entry on oeis.org

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

Offset: 1

Hugo Pfoertner, Nov 29 2020

			2.536150710120409525643838222345019049081863024335333926526148385147...

Index entries for algebraic numbers, degree 4.

Cf. A001622, A019881, A102208.

Cf. A118273 (cube), A122553 (regular octahedron), A363437 (regular tetrahedron), A363438 (regular dodecahedron).

RealDigits[4 * Sqrt[GoldenRatio + 2]/3, 10, 120][[1]] (* Amiram Eldar, Jun 02 2023 *)

PARI
```
4/3*sqrt(2+(1+sqrt(5))/2)
```

Equals 4*sqrt(2 + phi)/3 where phi = A001622.

Equals A102208 / A019881 ^ 3. - Amiram Eldar, Jun 02 2023

A118273 Decimal expansion of (4/3)^(3/2).

Original entry on oeis.org

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

Offset: 1

Eric W. Weisstein, Apr 21 2006

The volume of the cube inscribed in the unit-radius sphere. - Amiram Eldar, Jun 02 2023

			1.539600717839002038...

Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 5.24, p. 412.

Elliott H. Lieb, Residual entropy of square ice, Phys. Rev. 162 (1967) 162-172.
James Propp, The many faces of alternating-sign matrices, 2002.
Scenta server, Lieb's square ice constant. [Broken link]
Eric Weisstein's World of Mathematics, Lieb's Square Ice Constant.
Wikipedia, Lieb's square ice constant.
Index entries for algebraic numbers, degree 2.

Cf. A020784, A054759.

Cf. A122553 (octahedron), A339259 (regular icosahedron), A363437 (regular tetrahedron), A363438 (regular dodecahedron).

evalf(sqrt((4/3)^3)) ; # R. J. Mathar, Mar 29 2012

RealDigits[(4/3)^(3/2),10,120][[1]] (* Harvey P. Dale, Aug 06 2015 *)

(4/3)^(3/2) \\ Stefano Spezia, Dec 15 2024

Equals 8 * A020784.

A363438 Decimal expansion of the volume of the regular dodecahedron inscribed in the unit-radius sphere.

Original entry on oeis.org

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

Offset: 1

Amiram Eldar, Jun 02 2023

			2.78516386312262296729255491273594698789932177207633...

Eric Weisstein's World of Mathematics, Regular Dodecahedron.
Wikipedia, Regular dodecahedron.
Index entries for algebraic numbers, degree 4.

Cf. A118273 (cube), A122553 (regular octahedron), A339259 (regular icosahedron), A363437 (regular tetrahedron).
Cf. A001622.
Other constants related to the regular dodecahedron: A102769, A131595, A179296, A232810, A237603, A239798, A341906.

RealDigits[(2*(5 + Sqrt[5]))/(3*Sqrt[3]), 10, 120][[1]]

2*sqrt(5+sqrt(5))/sqrt(27) \\ Charles R Greathouse IV, Feb 07 2025

Equals 2*sqrt(5+sqrt(5))/(3*sqrt(3)).
Equals 4*(phi+2)/(3*sqrt(3)), where phi is the golden ratio (A001622).
Equals A102769 / A179296 ^ 3.

cp's OEIS Frontend

A122553 a(0)=1, a(n)=3 for n > 0.

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A339259 Decimal expansion of the volume of the regular icosahedron inscribed in the unit sphere.

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A118273 Decimal expansion of (4/3)^(3/2).

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A363438 Decimal expansion of the volume of the regular dodecahedron inscribed in the unit-radius sphere.

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