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A356869
Decimal expansion of 4 / sqrt(5).
1
1, 7, 8, 8, 8, 5, 4, 3, 8, 1, 9, 9, 9, 8, 3, 1, 7, 5, 7, 1, 2, 7, 3, 3, 8, 9, 3, 4, 9, 8, 5, 0, 2, 0, 9, 8, 8, 3, 5, 2, 4, 9, 4, 6, 8, 7, 6, 8, 9, 2, 2, 0, 5, 7, 9, 4, 1, 6, 7, 1, 7, 7, 9, 6, 3, 2, 8, 4, 1, 6, 7, 4, 0, 5, 1, 0, 2, 4, 3, 9, 1, 9, 5, 3, 1, 5, 3, 1, 5, 2, 6, 7, 0, 3, 0, 2, 5
OFFSET
1,2
COMMENTS
The area of a golden rectangle inscribed in a unit circle.
The width and height of the rectangle are:
W = sqrt(2 - 2 / sqrt(5)) = A179290.
H = sqrt(2 + 2 / sqrt(5)) = A121570.
FORMULA
Equals [1; 1, 3, 1, 2] (periodic continued fraction expansion). - Peter Luschny, Sep 02 2022
Equals 1/A204188. - Alois P. Heinz, Sep 02 2022
EXAMPLE
1.7888543819998317...
MAPLE
parse(substring(convert(evalf(4 / sqrt(5), 105), string), 1..98));
MATHEMATICA
RealDigits[4 / Sqrt[5], 10, 105][[1]][[Range[1, 97]]]
PROG
(MATLAB) cell2mat(struct2cell(struct(vpa(4 / sqrt(5), 105)))); ans(1:98)
CROSSREFS
KEYWORD
nonn,cons,easy
AUTHOR
Michal Paulovic, Sep 01 2022
STATUS
approved