$\begin{align}  & 2k-1+2k+1+2k+3={{(2k+1)}^{2}}-20 \\  & 6k+3=4{{k}^{2}}+4k+1-20 \\  & 4{{k}^{2}}-2k-22=0 \\  & 2{{k}^{2}}-k-11=0 \\ \end{align}$