L1 norm of characteristic coefficients

Let $A$ be a $7\times 7$ real matrix with $\mathrm{rank}(A)=1$. Suppose the trace of $A^2$ is $2025$. Let the characteristic polynomial of $A$ be written as $\sum_{n=0}^7 a_n x^n$. Then $\sum_{n=0}^7|a_n|$ is __________ (answer in integer)