A236557 Vertex solid angle (steradians) in a regular icosahedron.

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

Offset: 1

Author

Stanislav Sykora, Jan 28 2014

Keywords

• nonn
• cons
• easy

Examples

			2.6345470260447546596513034674924022914118092285116431884051417273...
		

Links

• Stanislav Sykora, Table of n, a(n) for n = 1..2000
• Wikipedia, Platonic solid.

Crossrefs

Cf. Analogs: A236555 (tetrahedron), A236556 (octahedron), A019669 (cube), A236558 (dodecahedron).

Programs

Mathematica

RealDigits[2*Pi - 5*ArcSin[2/3], 10, 120][[1]] (* Amiram Eldar, May 22 2023 *)

PARI

2*Pi-5*asin(2/3)

Formula

Equals 2*Pi - 5*arcsin(2/3).