It Isn't As Hard As It Looks

Number Theory Level 3

The sequence \(a_0,a_1,a_2,\dots\) satisfies \[a_{m+n} + a_{m-n} = \frac{1}{2}(a_{2m}+a_{2n})\]

for all non-negative integers with \(m\geq n\). If \(a_1 = 1\), determine the value of \[a_{1995}\]