The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A239798 Decimal expansion of the midsphere radius in a regular dodecahedron with unit edges. 7
 1, 3, 0, 9, 0, 1, 6, 9, 9, 4, 3, 7, 4, 9, 4, 7, 4, 2, 4, 1, 0, 2, 2, 9, 3, 4, 1, 7, 1, 8, 2, 8, 1, 9, 0, 5, 8, 8, 6, 0, 1, 5, 4, 5, 8, 9, 9, 0, 2, 8, 8, 1, 4, 3, 1, 0, 6, 7, 7, 2, 4, 3, 1, 1, 3, 5, 2, 6, 3, 0, 2, 3, 1, 4, 0, 9, 4, 5, 1, 2, 2, 4, 8, 5, 3, 6, 0, 3, 6, 0 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS In a regular polyhedron, the midsphere is tangent to all edges. Apart from leading digits the same as A019863 and A019827. - R. J. Mathar, Mar 30 2014 LINKS Stanislav Sykora, Table of n, a(n) for n = 1..2000 Wikipedia, Platonic solid FORMULA Equals phi^2/2, phi being the golden ratio (A001622). Also (3+sqrt(5))/4. EXAMPLE 1.30901699437494742410229341718281905886015458990288143106772431135263... MAPLE Digits:=100: evalf((3+sqrt(5))/4); # Wesley Ivan Hurt, Mar 27 2014 MATHEMATICA RealDigits[GoldenRatio^2/2, 10, 105][[1]] (* Vaclav Kotesovec, Mar 27 2014 *) PROG (PARI) (3+sqrt(5))/4 CROSSREFS Cf. A001622, Midsphere radii in Platonic solids: A020765 (tetrahedron), A020761 (octahedron), A010503 (cube), A019863 (icosahedron). Sequence in context: A167004 A287632 A259346 * A019827 A329284 A269557 Adjacent sequences:  A239795 A239796 A239797 * A239799 A239800 A239801 KEYWORD nonn,cons,easy AUTHOR Stanislav Sykora, Mar 27 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 27 09:44 EST 2020. Contains 332301 sequences. (Running on oeis4.)