|
| |
|
|
A020837
|
|
Decimal expansion of 1/sqrt(80) = sqrt(5)/20.
|
|
8
|
|
|
|
1, 1, 1, 8, 0, 3, 3, 9, 8, 8, 7, 4, 9, 8, 9, 4, 8, 4, 8, 2, 0, 4, 5, 8, 6, 8, 3, 4, 3, 6, 5, 6, 3, 8, 1, 1, 7, 7, 2, 0, 3, 0, 9, 1, 7, 9, 8, 0, 5, 7, 6, 2, 8, 6, 2, 1, 3, 5, 4, 4, 8, 6, 2, 2, 7, 0, 5, 2, 6, 0, 4, 6, 2, 8, 1, 8, 9, 0, 2, 4, 4, 9, 7, 0, 7, 2, 0, 7, 2, 0, 4, 1, 8, 9, 3, 9, 1, 1, 3
(list;
constant;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,4
|
|
|
COMMENTS
|
Multiplied by 100, this is sqrt(125). - Alonso del Arte, Jan 06 2013
Multiplied by 10, this is sqrt(5)/2. As such, it appears in the pythagorean tree as the ratio of the distance between 2 consecutive square centers divided by the length of the initial square (see CNRS link) - Michel Marcus, Feb 20 2013
The two-dimensional Steinitz constant K_2(0,0), related to sum of vectors, is sqrt(5)/2. - Jean-François Alcover, Jun 04 2014
|
|
|
REFERENCES
|
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 3.13 Steinitz constants, p. 241.
|
|
|
LINKS
|
Ivan Panchenko, Table of n, a(n) for n = 0..1000
Étienne Ghys and Jos Leys, Un arbre pythagoricien — Images des Mathématiques, CNRS, 2013.
|
|
|
FORMULA
|
1/sqrt(80) = sqrt(5)/20 = (-1 + 2*phi)/20, with phi from A001622.
|
|
|
EXAMPLE
|
sqrt(5)/20 = 0.111803398874989484820458683436563811772...
sqrt(5)/2 = 1.118033988749894848204586834365638117720...
|
|
|
MATHEMATICA
|
RealDigits[1/Sqrt[80], 10, 120][[1]] (* Harvey P. Dale, May 01 2012 *)
|
|
|
PROG
|
(PARI) sqrt(1/80) \\ Charles R Greathouse IV, Apr 25 2016
|
|
|
CROSSREFS
|
c = (1/10)*(A001622 - 1/2) = (1/10)*(7/2 - A079585).
Sequence in context: A144455 A251866 A300713 * A248679 A175574 A195342
Adjacent sequences: A020834 A020835 A020836 * A020838 A020839 A020840
|
|
|
KEYWORD
|
nonn,cons
|
|
|
AUTHOR
|
N. J. A. Sloane.
|
|
|
STATUS
|
approved
|
| |
|
|
