OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Golden Spiral.
Eric Weisstein's World of Mathematics, Golden Rectangle.
Eric Weisstein's World of Mathematics, Logarithmic Spiral.
Wikipedia, Golden spiral.
FORMULA
sqrt(1+1/sqrt(5))*sqrt(1+b^2)/b, where b=2*log(phi)/Pi, and phi=(1+sqrt(5))/2.
EXAMPLE
4.10703804944010238128...
MATHEMATICA
b=2*Log[GoldenRatio]/Pi; RealDigits[Sqrt[1+1/Sqrt[5]]*Sqrt[1 + b^2]/b, 10, 120][[1]]
PROG
(PARI) phi = (1+sqrt(5))/2; b = 2*log(phi)/Pi; sqrt(1+1/sqrt(5))*sqrt(1+b^2)/b \\ Michel Marcus, Dec 23 2017
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Amiram Eldar, Dec 20 2017
STATUS
approved