A236555 Decimal expansion of the steradian solid angle subtended by one triangular facet of the cuboctahedron.

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

Offset

0,1

Comments

Also the vertex solid angle of a regular tetrahedron.

Links

Stanislav Sykora, Table of n, a(n) for n = 0..2000

Eric Weisstein's World of Mathematics, Cuboctahedron

Eric Weisstein's World of Mathematics, Spherical Polygon

Wikipedia, Platonic solid

Formula

arccos(23/27).

3*arcsin(2*sqrt(2)/3) - Pi. - Bradley Klee, Oct 04 2018

8*A236555 + 6*A236556 = 4*Pi. - Bradley Klee, Oct 04 2018

Example

0.55128559843253080794214415146445924293385062869017869619170040868416...

Mathematica

RealDigits[N[ArcCos[23/27], 107]][[1]] (* T. D. Noe, Jan 29 2014 *)

Crossrefs

Cf. A236556. Icosidodecahedron: A319881, A319883. Vertex Angles: A019669, A236557, A236558.

Sequence in context: A156696 A232651 A145227 * A282969 A046095 A322545

Adjacent sequences: A236552 A236553 A236554 * A236556 A236557 A236558

Keyword

nonn,cons,easy

Author

Stanislav Sykora, Jan 28 2014

Extensions

Definition corrected by Bradley Klee, Oct 04 2018

Status

approved