The correct function notation that corresponds to the recursively defined formula \( a_1 = -3 \) and \( a_n = a_{n-1} + 4 \) is:
f(1) = -3; f(n) = f(n-1) + 4
This captures the initial condition and the recursive relationship accurately. Thus, the answer is:
f(1)=β3; f(n)=f(nβ1)+4