Maybe easier, if limited to the specific case of an input in the range [0..63] and a divisor of 7, but not necessarily faster. Keep in mind the latency of a memory read is typically around 4 cycles, and at least some architectures have a tighter limit on the number of concurrent memory transactions than the number of concurrent integer math instructions, and keep in mind the article is generalizing beyond the initial problem involving the numbers 63 and 7- if you have more than a couple different divisors, and if you want to allow the input to go as large as possible, then a lookup table quickly becomes wasteful and impractical.