Unrolling the computation of the series, it is possible to compute f(n) using only f(n-4) and f(n-8): f(n) = 7*f(n-4)-f(n-8) So, using 4-vector operations, yo

Unrolling the computation of the series, it is possible to compute f(n) using only f(n-4) and f(n-8): f(n) = 7*f(n-4)-f(n-8) So, using 4-vector operations, you can compute 4 numbers in one step.