I'm working on a software engineering question and need an explanation and answer to help me learn.

Implement a Scheme/Racket function (seq f (start step end)) that produces a list of values (f(start),f(start+step),…,f(start+n*step)), where n is the largest integer such that $start+n\cdot step\le end$ and $start+(n+1)\cdot step>end$

$\mathrm{You\; cannot\; use\; the\; built-in\; map\; function.<br>}$