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A339259
Decimal expansion of the volume of the regular icosahedron inscribed in the unit sphere.
8
2, 5, 3, 6, 1, 5, 0, 7, 1, 0, 1, 2, 0, 4, 0, 9, 5, 2, 5, 6, 4, 3, 8, 3, 8, 2, 2, 2, 3, 4, 5, 0, 1, 9, 0, 4, 9, 0, 8, 1, 8, 6, 3, 0, 2, 4, 3, 3, 5, 3, 3, 3, 9, 2, 6, 5, 2, 6, 1, 4, 8, 3, 8, 5, 1, 4, 7, 0, 7, 5, 1, 2, 0, 2, 2, 7, 1, 8, 2, 6, 7, 1, 2, 5, 0, 1, 1
OFFSET
1,1
FORMULA
Equals 4*sqrt(2 + phi)/3 where phi = A001622.
Equals A102208 / A019881 ^ 3. - Amiram Eldar, Jun 02 2023
EXAMPLE
2.536150710120409525643838222345019049081863024335333926526148385147...
MATHEMATICA
RealDigits[4 * Sqrt[GoldenRatio + 2]/3, 10, 120][[1]] (* Amiram Eldar, Jun 02 2023 *)
PROG
(PARI) 4/3*sqrt(2+(1+sqrt(5))/2)
CROSSREFS
Cf. A118273 (cube), A122553 (regular octahedron), A363437 (regular tetrahedron), A363438 (regular dodecahedron).
Sequence in context: A091807 A085825 A198140 * A340066 A212614 A037852
KEYWORD
nonn,cons
AUTHOR
Hugo Pfoertner, Nov 29 2020
STATUS
approved