OFFSET
1,1
COMMENTS
The fractal is taken scaled to unit length from curve start to end.
With complex b = 1+2i, the hull sides are a countably infinite set: +-(4-i)/b^2, +-2/b^2, and 2*i^d/b^k for d=0..3 and k>=3. The sum of their magnitudes is the present constant.
LINKS
Kevin Ryde, Table of n, a(n) for n = 1..10000
Kevin Ryde, Iterations of the R5 Dragon Curve, see index "HBf".
FORMULA
Equals (6 + 2*sqrt(5) + 2*sqrt(17)) / 5.
Equals (sqrt(8*sqrt(5*17) + 88) + 6) / 5.
Largest root of 625*x^4 - 3000*x^3 + 1000*x^2 + 6240*x - 2736 = 0 (all roots are real).
EXAMPLE
3.7436694412469800984922334098821413...
MATHEMATICA
RealDigits[(6 + 2*Sqrt[5] + 2*Sqrt[17])/5, 10, 120][[1]] (* Amiram Eldar, Jun 15 2023 *)
PROG
(PARI) my(c=352+32*quadgen(5*17*4)); a_vector(len) = my(s=10^(len-2)); digits(sqrtint(floor(c*s^2)) + floor(12*s));
CROSSREFS
KEYWORD
cons,nonn
AUTHOR
Kevin Ryde, Nov 06 2021
STATUS
approved