Project Euler Forum

Problem 810 (View Problem)
Xor primes are listed as 2,3,7...
But since 7 = 5 xor 2, why is 7 an Xor prime? Are we just to consider if it is an xor of lower xor-primes?

Caesum wrote: Sat Jul 29, 2023 2:21 pm Problem 810 (View Problem)
Xor primes are listed as 2,3,7...
But since 7 = 5 xor 2, why is 7 an Xor prime? Are we just to consider if it is an xor of lower xor-primes?

Note that $\oplus$ (XOR) and $\otimes$ (Xor product) are distinct operators.
$7 = 5 \oplus 2$, but a Xor prime is a positive integer that cannot be decomposed non-trivially via $\otimes$.