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).
Euler's Formula. What is great about Euler's formula is that it can be understood by almost anyone, as it is so simple to write down. Euler's formula can be understood by someone in Year 7, but is also interesting enough to be studied in universities as part of the mathematical area called topology. Euler's formula deals with shapes called Polyhedra. A Polyhedron is a closed solid shape which has flat faces and straight edges. An example of a polyhedron would be a cube, whereas a cylinder is not a polyhedron as it has curved edges.