login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A020765 Decimal expansion of 1/sqrt(8). 9
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 *)

PROG

(PARI) sqrt(1/8) \\ Charles R Greathouse IV, Apr 25 2016

CROSSREFS

Cf. Midsphere radii in Platonic solids:

A020761 (octahedron),

A010503 (cube),

A019863 (icosahedron),

A239798 (dodecahedron).

Sequence in context: A096634 A105439 A142972 * A112756 A121795 A253027

Adjacent sequences:  A020762 A020763 A020764 * A020766 A020767 A020768

KEYWORD

nonn,cons

AUTHOR

N. J. A. Sloane

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 4 05:11 EST 2016. Contains 278748 sequences.