27020 (Gheorghe Szöllösy)
Să se calculeze suma ∑ k = 0 [ n 2 ] [ n 2 ] {\displaystyle \sum _{k=0}^{\left[{\frac {n}{2}}\right]}\left[{\dfrac {n}{2}}\right]}
![{\displaystyle \sum _{k=0}^{\left[{\frac {n}{2}}\right]}\left[{\dfrac {n}{2}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/8d81c810a2cedf8d68dfe941184b9d8ca0024486)