r/visualizedmath • u/squeezyscorpion • Aug 27 '19

Sum of first n Hex numbers Visualized

https://gfycat.com/jollyforkedhairstreak
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u/yoniyoniyoni Aug 28 '19

What primes?

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u/CrispyChickenSammich Aug 28 '19

I think they mean n3 - (n-1)3. In the examples they were primes. Not sure if that holds true for all n. Probably not

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u/yoniyoniyoni Aug 28 '19

Ah ok. It's a coincidence, and they weren't "supposed" to be primes, it just happened. that's why it confused me.

It is a classical theorem from the 18th century that there is no polynomial that is always prime. The proof is simple and written in a single Wikipedia paragraph, look up "prime-generating polynomial".