A344075 Decimal expansion of arccos(-sqrt((5+2*sqrt(5))/15)).

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

Offset

1,1

Comments

Decimal expansion of the dihedral angle (radians) of an icosidodecahedron. Equals approximately 142.62 degrees.

Links

Table of n, a(n) for n=1..92.

Wikipedia, Icosidodecahedron

Example

2.489234513805425052467...

Mathematica

RealDigits[ArcCos[-Sqrt[(5 + 2 Sqrt[5])/15]], 10, 200][[1]]

Prog

(PARI) acos(-sqrt((5+2*sqrt(5))/15)) \\ Michel Marcus, May 09 2021

Crossrefs

Cf. A179450 (icosidodecahedron volume), A179451 (icosidodecahedron surface area).

Sequence in context: A193846 A255908 A341107 * A011402 A131625 A196000

Adjacent sequences: A344072 A344073 A344074 * A344076 A344077 A344078

Keyword

cons,nonn

Author

Wesley Ivan Hurt, May 08 2021

Status

approved