> There exists a non-serious branch of math. Try paging through OEIS sometime... https://oeis.org/ https://oeis.org/ There are many seemingly silly bits of ma

> There exists a non-serious branch of math. Try paging through OEIS sometime... https://oeis.org/ https://oeis.org/ There are many seemingly silly bits of math. However, the answer in mathematics is often not the most interesting part (or even interesting at all), and a lot of important mathematics was created to produce answers for seemingly silly or pointless questions. If you have a silly math problem and it's answered quickly-- well then it didn't waste much time. If you have a silly math problem and it's fiendishly hard to solve, then the discoveries that lead to the solution aren't silly-- they teach us how to do something we didn't know how to do before and may have important and useful implications. For things like these primarily proofs the mathematical discoveries have already happened (at least until someone comes up with a new one!)-- and the ongoing effort is in engineering for numerical software and the IT work required to manage the computation in a cost effective manner. Some families of primes have important mathematical structure that has a lot of known consequences, special algorithms that work with them (such as repunit primes in base 2), etc. Other's don't, or at least don't have any that we know of yet-- but they still divide up the literally infinite space of primes and give people interested in studying them a subset they can focus on.