Not to be confused with Ball bearing. Bearing balls are special highly spherical and smooth balls, most commonly used in ball bearings, but also used as components in things like freewheel mechanisms. The balls come in many different grades.
Euler Prime. Let a prime number generated by Euler's prime-generating polynomial be known as an Euler prime. Then the first few Euler primes occur for , 2, ..., 39, 42, 43, 45, ... (OEIS A056561), corresponding to the primes 43, 47, 53, 61, 71, 83, 97, 113, 131, 151, 173, ... (OEIS A005846).
Around 1741, Euler began to study the following two questions: 1  Given an integer N, describe the primes p = 2 for which p = x2 + Ny2 is solvable with integers x and y; 2  Given an integer N, describe the primes p = 2 for which p divides m (p|m), where m is any integer of the form m = x2 + Ny2, with integers x and y.