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A020765 Decimal expansion of 1/sqrt(8). 8
3, 5, 3, 5, 5, 3, 3, 9, 0, 5, 9, 3, 2, 7, 3, 7, 6, 2, 2, 0, 0, 4, 2, 2, 1, 8, 1, 0, 5, 2, 4, 2, 4, 5, 1, 9, 6, 4, 2, 4, 1, 7, 9, 6, 8, 8, 4, 4, 2, 3, 7, 0, 1, 8, 2, 9, 4, 1, 6, 9, 9, 3, 4, 4, 9, 7, 6, 8, 3, 1, 1, 9, 6, 1, 5, 5, 2, 6, 7, 5, 9, 7, 1, 2, 5, 9, 6, 8, 8, 3, 5, 8, 1, 9, 1, 0, 3, 9, 3 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Multiplied by 10, this is the real and the imaginary part of sqrt(25i). - Alonso del Arte, Jan 11 2013

Radius of the midsphere (tangent to the edges) in a regular tetrahedron with unit edges. - Stanislav Sykora, Nov 20 2013

LINKS

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Wikipedia, Tetrahedron

Wikipedia, Platonic solid

FORMULA

A010503 divided by 2.

EXAMPLE

1/sqrt(8) = 0.353553390593273762200422181052424519642417968844237018294...

MAPLE

Digits:=100; evalf(1/sqrt(8)); # Wesley Ivan Hurt, Mar 27 2014

MATHEMATICA

RealDigits[N[1/Sqrt[8], 200]] (* Vladimir Joseph Stephan Orlovsky, May 27 2010 *)

CROSSREFS

Cf. Midsphere radii in Platonic solids:

A020761 (octahedron),

A010503 (cube),

A019863 (icosahedron),

A239798 (dodecahedron).

Sequence in context: A096634 A105439 A142972 * A112756 A121795 A249384

Adjacent sequences:  A020762 A020763 A020764 * A020766 A020767 A020768

KEYWORD

nonn,cons

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified December 18 03:29 EST 2014. Contains 252079 sequences.