A179452 Decimal expansion of sqrt(5 + 2*sqrt(5))/2, the height of a regular pentagon and midradius of an icosidodecahedron with side length 1.

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

Offset

1,2

Comments

Icosidodecahedron: 32 faces, 30 vertices, and 60 edges.

Height of a regular pentagon with side length 1. - Jared Kish, Oct 16 2014

Volume of a regular decagonal prism with unit side length and height 2. - Wesley Ivan Hurt, May 04 2021

Links

Table of n, a(n) for n=1..105.

Eric Weisstein's World of Mathematics, Icosidodecahedron

Eric Weisstein's World of Mathematics, Pentagon

Index entries for algebraic numbers, degree 4

Formula

Equals sqrt(5+2*sqrt(5))/2.

Example

1.53884176858762670128514528801845491200335107176889621351957812518743...

Maple

sqrt(5+2*sqrt(5.))/2

Mathematica

RealDigits[Sqrt[5+2Sqrt[5]]/2, 10, 120][[1]] (* Harvey P. Dale, Jun 23 2017 *)

Prog

(PARI) sqrt(5+2*sqrt(5))/2

Crossrefs

Cf. A010527, A102208, A179290, A179292, A179294, A179449, A179450, A179451.

Sequence in context: A161488 A010484 A174930 * A079810 A300884 A337440

Adjacent sequences: A179449 A179450 A179451 * A179453 A179454 A179455

Keyword

nonn,cons,easy

Author

Vladimir Joseph Stephan Orlovsky, Jul 14 2010

Extensions

Partially rewritten by Charles R Greathouse IV, Feb 03 2011

Edited by M. F. Hasler, Oct 16 2014

Status

approved