Let for \( n=1,2,\ldots,50 \), \( S_n \) be the sum of the infinite geometric progression whose first term is \( n^{2} \) and whose common ratio is \( \dfrac{1}{(n+1)^{2}} \). Then the value of \( \dfrac{1}{26}+\displaystyle\sum_{n=1}^{50}\!\left(S_n+\dfrac{2}{n+1}-n-1\right) \) is equal to __________.