MathCastle
Counting & ProbabilityChallengeRecursion, Catalan Numbers & Generating Functions

Recursion, Catalan Numbers & Generating Functions · Challenge problem

Starting from ∑n≥0Fnxn=x1−x−x2\sum_{n\ge 0}F_nx^n=\dfrac{x}{1-x-x^2}, evaluate the sum ∑n≥1Fn2n\displaystyle\sum_{n\ge 1}\frac{F_n}{2^n}.