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A236367 Dihedral angle in a regular icosahedron (radians). 4
2, 4, 1, 1, 8, 6, 4, 9, 9, 7, 3, 6, 2, 8, 2, 6, 8, 7, 5, 0, 0, 7, 8, 4, 6, 7, 2, 3, 4, 6, 6, 1, 8, 2, 1, 8, 8, 8, 0, 0, 6, 6, 3, 4, 8, 5, 3, 2, 7, 3, 9, 2, 1, 3, 0, 2, 6, 5, 9, 9, 5, 1, 0, 0, 8, 4, 5, 9, 9, 7, 5, 0, 6, 6, 1, 9, 4, 4, 1, 8, 5, 9, 8, 3, 2, 5, 5, 1, 4, 1, 7, 5, 2, 2, 6, 4, 3, 5, 6, 7, 7, 7, 4, 0, 5 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Stanislav Sykora, Table of n, a(n) for n = 1..2000

Wikipedia, Platonic solid

FORMULA

2*arctan(phi^2) = 2*arctan(A001622^2) = 2*arctan((3+sqrt(5))/2)

EXAMPLE

2.41186499736282687500784672346618218880066348532739213...

PROG

(PARI) 2*atan((3+sqrt(5))/2)

CROSSREFS

Cf. A001622, Platonic solids dihedral angles: A137914 (tetrahedron), A156546 (octahedron), A019669 (cube), A137218 (dodecahedron).

Sequence in context: A207260 A187913 A201287 * A197489 A103161 A030420

Adjacent sequences:  A236364 A236365 A236366 * A236368 A236369 A236370

KEYWORD

nonn,cons,easy

AUTHOR

Stanislav Sykora, Jan 23 2014

STATUS

approved

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Last modified May 28 17:57 EDT 2017. Contains 287241 sequences.