The great thing about 239. And another great thing!pic.twitter.com/pL35E5BbiV
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If I were mistaken about the primality of 239 it's quite plausible I would remain ignorant about my error for the rest of my life and suffer no harm for it. If I was mistaken about the existence of my right hand there are hundreds of moments in a day where I ought to notice it.
A primality test is much more complicated (internally) than the immediate reality of your hand
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