The version of this joke that I heard/tell goes like this:

A mathematician, physicist, engineer, and computer programmer are all challenged to determine whether all odd numbers are prime.

The mathematician says, “One is prime, three is prime, five is prime, seven is prime, nine is not prime - nope.”

The physicist said, “One is prime, three is prime, five is prime, seven is prime, nine is probably experimental error because eleven and thirteen are prime - yep.”

The engineer says, “One is prime, three is prime, five is prime, seven is prime, nine is prime, eleven is prime - yep.”

The computer programmer says, “One is prime, one is prime, one is prime, one is prime ….”

Here, courtesy of the internet and Dave Berry’s blog, is some more material.

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Computational linguist: 3 is an odd prime, 5 is an odd prime, 7 is an odd prime, 9 is a very odd prime,…

Chemist: 1 prime, 3 prime, 5 prime… hey, let’s publish!

Programmer: 3 is prime, 5 is prime, 7 is prime, 9 will be fixed in the next release …

Richard Nixon: Put nine on the enemies list. I’m gonna get that number.