OFFSET
0,10
COMMENTS
Related to modular functions and approximations to Pi : K210 is one of the most famous singular value calculated by Ramanujan. -2/sqrt(210)*log(K210/4) = 3.14159265358979323847198.. agrees with Pi to 20 decimal places
REFERENCES
L. Berggren, J. Borwein and P. Borwein, "Pi a source Book", second edition, Springer, p. 592
FORMULA
K210=(sqrt(2)-1)^2*(2-sqrt(3))*(sqrt(7)-sqrt(6))^2*(8-3*sqrt(7))*(sqrt(10)-3)^2*(sqrt(15)-sqrt(14))*(4-sqrt(15))^2*(6-sqrt(35))
EXAMPLE
0.0000000005202524184706450480489....
CROSSREFS
KEYWORD
cons,nonn
AUTHOR
Benoit Cloitre, Dec 03 2002
STATUS
approved