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Klasično zlo | Classical evil #4

Let (a_n)_{n\in \mathbb{N}} be real sequence defined by a_{1}=\frac{1}{4} and the recurrence a_{n}= \frac{1}{4}(1+a_{n-1})^{2}, \forall n\geq 2.

Find the minimum real \lambda such that for any non-negative reals x_{1},x_{2},\dots,x_{2002}, it holds \sum_{k=1}^{2002}A_{k}\leq \lambda a_{2002}, where A_{k}= \frac{x_{k}-k}{(x_{k}+\cdots+x_{2002}+\frac{k(k-1)}{2}+1)^{2}}, k \geq 1.

Neka je (a_n)_{n\in \mathbb{N}} realni niz definiran s a_{1}=\frac{1}{4} i s rekurzijom a_{n}= \frac{1}{4}(1+a_{n-1})^{2}, \forall n\geq 2.
Odredite minimum realnog broja \lambda tako da za svaki nenegativni realni broj x_{1},x_{2},\dots,x_{2002} vrijedi \sum_{k=1}^{2002}A_{k}\leq \lambda a_{2002}, gdje A_{k}= \frac{x_{k}-k}{(x_{k}+\cdots+x_{2002}+\frac{k(k-1)}{2}+1)^{2}}, k \geq 1.