The primes that can't be written as the sum of a square and a prime. – math.stackexchange.com

I stumbled upon A065377, the list of primes which can't be written in the form $p+k^2$ ($p$ prime and k>0 being an integer), and it's $2, 5, 13, 31, 37, 61, 127, 379, 439, 571, 829, 991, 1549, ...