%I #14 Feb 01 2021 03:08:41
%S 1,6,8,4,8,1,3,1,4,4,4,8,9,5,7,6,0,9,6,3,1,6,5,5,4,3,3,7,3,8,0,0,7,8,
%T 2,3,0,2,3,7,0,6,3,8,8,2,4,5,7,0,8,6,8,2,0,9,4,3,1,7,6,1,8,8,5,9,5,0,
%U 5,6,0,0,2,8,0,4,9,4,5,4,9,8,9,1,0,8
%N Decimal expansion of Sum_{n >= 1} 2^(1-n)/Fibonacci(n).
%F Equals Sum_{n>=0} 1/A063727(n) = Sum_{n>=1} 1/A085449(n) = 2 * Sum_{n>=1} 1/A103435(n) = 4 * Sum_{n>=1} 1/A209084(n). - _Amiram Eldar_, Feb 01 2021
%e 1.684813144489576096316554337380078230...
%t x = N[Sum[2^(1 - n)/Fibonacci[n], {n, 1, 500}], 100]
%t RealDigits[x][[1]]
%o (PARI) suminf(n=1, 2^(1-n)/fibonacci(n)) \\ _Michel Marcus_, Feb 01 2021
%Y Cf. A000045, A269992.
%Y Cf. A063727, A085449, A103435, A209084.
%K nonn,cons,easy
%O 1,2
%A _Clark Kimberling_, Mar 12 2016
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