# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a269991 Showing 1-1 of 1 %I A269991 #14 Feb 01 2021 03:08:41 %S A269991 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 A269991 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 A269991 5,6,0,0,2,8,0,4,9,4,5,4,9,8,9,1,0,8 %N A269991 Decimal expansion of Sum_{n >= 1} 2^(1-n)/Fibonacci(n). %F A269991 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 A269991 1.684813144489576096316554337380078230... %t A269991 x = N[Sum[2^(1 - n)/Fibonacci[n], {n, 1, 500}], 100] %t A269991 RealDigits[x][[1]] %o A269991 (PARI) suminf(n=1, 2^(1-n)/fibonacci(n)) \\ _Michel Marcus_, Feb 01 2021 %Y A269991 Cf. A000045, A269992. %Y A269991 Cf. A063727, A085449, A103435, A209084. %K A269991 nonn,cons,easy %O A269991 1,2 %A A269991 _Clark Kimberling_, Mar 12 2016 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE