OFFSET
0,1
COMMENTS
Minimal polynomial is 124x^2 - 150x + 45. - Charles R Greathouse IV, Jul 16 2024
FORMULA
Equals (3/124) (25 - sqrt(5)).
EXAMPLE
0.5507402908669405718610683789823078330135334267835...
MATHEMATICA
s = Sum[(Sin[k Pi/5])^2/2^k, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]
PROG
(PARI) suminf(k=0, (sin(k*Pi/5))^2>>k) \\ Charles R Greathouse IV, Jul 16 2024
(PARI) (75-sqrt(45))/124 \\ Charles R Greathouse IV, Jul 16 2024
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Jul 16 2024
STATUS
approved