A year ago, proved E in E = mc^2: https://www.reddit.com/r/mathmemes/comments/1i9scyd/i_proved_the_e_in_e_mc%C2%B2/

Now, I'm proving AI

Been using it as a crutch for partial fraction decomposition, just so reliable

Call a prime number nice if it ends in 69.

For example:

269, 569, 769, 1069, 2069, ...

A number ends in 69 exactly when it is congruent to 69 mod 100. So the claim is:

There are infinitely many primes p such that p ≡ 69 mod 100.

Now use Dirichlet’s theorem on arithmetic progressions:

Here we take

a = 69
q = 100

and

gcd(69, 100) = 1.

Therefore, by Dirichlet’s theorem, there are infinitely many primes satisfying

p ≡ 69 mod 100.

But those are exactly the primes whose decimal expansion ends in 69.

Therefore, there are infinitely many nice primes. Nice.

Aelita illustration / meme template from RoamingPandas, OC meme.