Prime number X

Prime number X

Elon Musk published the prime number X on his page. As you can see, this prime number actually has 1800 digits. Reddit users have started a fascinating discussion about this prime number. I liked these comments:

Watch out: there’s a sneaky 7 near the end of the tenth row.

It's pretty obvious someone tried a few tweaks until they found a configuration that actually gives a prime. But yeah, the digit 7 is the most visible one and surely the last change made - essentially that's the point where the author gave up on having a nicer solution :)

Now I'll remove all 1 from the drawing and we'll see what's left.

Prime number X without 1

As you can see, the number of eights in the lines does not correspond to the ideal pattern. And also this number 7. Yes, even Elon Musk is powerless against mathematics.

I’m interested in this question: how much money did Elon Musk pay for this work? Personally, I would not regret the largest amount possible. What could be greater than the SUM OF ALL NATURAL NUMBERS? Nothing. Who do I owe -$1/12? Why can you use this in physics, but you can’t pay for work?

Why 13?

No, today I will not tell you why the number 13 is considered unlucky. All numbers are the same. It is we who consider some numbers to be happy or unlucky, positive or negative. We will talk about the sum of two numbers on a watch dial. Why does adding two numbers on a watch dial equal 13? We see six pairs of such numbers on the clock. The explanation is very simple.

Why 13?

If we add 1 to one term and subtract 1 from another term, the sum will remain the same. This can be repeated many times and the result of the addition will not change. This property of addition can be observed not only on the watch dial, but also on the number line.

Sum on a number line

As the initial sum on the number line, you can take two adjacent numbers (top picture) or two numbers located next to the number we chose (bottom picture). I called such sums “Decomposition sums”.