Cool! 😎 Never heard of this before - thanks for sharing. (Except that mathematican himself, of course.)
Perhaps not what you were looking for, but here's another program of that kind. 😀
https://rudhar.com/prime/prime.htm
Edit: Some hints to that banchmark:
Link 1
Link 2
https://rosettacode.org/wiki/Sieve_of_Eratosthenes
http://ntheory.org/sieves/benchmarks.html
PS: Seems the benchmark was common for testing Pascal languages.
Edit: Found a PDF that explains the working of the sieve.
Edit: It is perhaps not 100% on-topic, but I know of a few fractal programs for PC/DOS, that are fun, too.
They are not crunching prime numbers, but are also math-related, and run on XTs (w/ FPU), even.
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