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A102208 Decimal expansion of the volume of an icosahedron with unit edge length. 34
2, 1, 8, 1, 6, 9, 4, 9, 9, 0, 6, 2, 4, 9, 1, 2, 3, 7, 3, 5, 0, 3, 8, 2, 2, 3, 6, 1, 9, 7, 1, 3, 6, 5, 0, 9, 8, 1, 0, 0, 2, 5, 7, 6, 4, 9, 8, 3, 8, 1, 3, 5, 7, 1, 8, 4, 4, 6, 2, 0, 7, 1, 8, 5, 5, 8, 7, 7, 1, 7, 0, 5, 2, 3, 4, 9, 0, 8, 5, 3, 7, 4, 7, 5, 6, 0, 0, 6, 0, 0, 3, 4, 9, 1, 1, 5, 9, 2, 8, 1 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Icosahedron
FORMULA
Equals 5 * (3 + sqrt(5))/12.
Equals 5*phi^2/6, phi being the golden ratio. - Stanislav Sykora, Nov 23 2013
EXAMPLE
2.181694990624912373503822...
MATHEMATICA
RealDigits[N[5/12*(3+Sqrt[5]), 200]][[1]] (* Vladimir Joseph Stephan Orlovsky, Feb 21 2011 *)
PROG
(PARI) 5*(3 + sqrt(5))/12 \\ G. C. Greubel, Jul 06 2017
CROSSREFS
Cf. A001622 (phi), A020829 (regular tetrahedron volume), A131594 (regular octahedron volume), A102769 (regular dodecahedron volume).
Cf. A071402.
Sequence in context: A284346 A318651 A083529 * A371650 A369779 A125911
KEYWORD
cons,nonn
AUTHOR
Bryan Jacobs (bryanjj(AT)gmail.com), Feb 17 2005
STATUS
approved

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Last modified July 23 23:47 EDT 2024. Contains 374575 sequences. (Running on oeis4.)