When input this number, the number of arrows in Knuth [NOOTH] notation is independent of the output.
When input this number, the number of arrows in Knuth [NOOTH] notation is independent of the output. This value is always next-to-last in a Collatz [cull-ATZ] sequence. A classic proof by contradiction sets this value equal to p squared over q squared, for integral p and q. This is the largest number n for which a to the n plus b to the n may equal (*) c to the n, for integral a, b, and c. Every even number can be expressed as the sum of this many primes. The largest known primes are one less than a power of this number. The number of vertices minus edges plus faces equals this value for most polyhedra. For 10 points, name this smallest and only even prime number.
When input this number, the number of arrows in Knuth [NOOTH] notation is independent of the output.
two