OFFSET
1,1
COMMENTS
The convex hull around the terdragon fractal has 14 sides and with unit length from curve start to end their lengths are four sqrt(3)/24 and two each 1/24, 1/8, sqrt(3)/8, 3/8, sqrt(37)/12. Their total is the perimeter.
LINKS
Kevin Ryde, Table of n, a(n) for n = 1..10000
Kevin Ryde, Iterations of the Terdragon Curve, see index "HBf".
FORMULA
Equals (13 + 5*sqrt(3) + 2*sqrt(37)) / 12.
Equals (13 + sqrt(223 + 20*sqrt(3*37))) / 12.
Largest root of ((12*x - 13)^2 - 223)^2 - 44400 = 0 (all its roots are real).
EXAMPLE
2.8188149248700688204697166831611246...
MATHEMATICA
RealDigits[(13+5*Sqrt[3]+2*Sqrt[37])/12, 10, 120][[1]] (* Harvey P. Dale, Dec 25 2021 *)
PROG
(PARI) my(c=223+20*quadgen(3*37*4)); a_vector(len) = my(s=10^(len-1)); digits((13*s + sqrtint(floor(c*s^2))) \12);
CROSSREFS
KEYWORD
AUTHOR
Kevin Ryde, Apr 17 2021
STATUS
approved