Everyone assumes aliens will know higher math. So much so that some people think encoding the orders of the first 26 sporadic groups would be obvious. (IDK why this is better than a list of primes)
But would it, though?
We name the groups by their orders, and think it's neat that exactly 26 are special in this way, like the 5 platonic solids.
But couldn't you do a lot with math and never really focus on these facts? It's not free from culture. math has a culture.
Imagining aliens that never really get digital (finger based) math. Their math is all analog, about measurements and estimates. Their computers don't have crystals, cycles or clocks.
They find discrete math silly and amusing. Because that's not how the world is *obviously* --
The develop better understands of statistics and prediction than we've ever been able to master. But have no notion of anything like an integer or a bit.
Imagine if they didn't have "=" and the concept of equality. Much of our math would make no sense to them.