User blog comment:Vel!/Call for math facts/@comment-1605058-20140730153802

Few examples me with Deedlit came up with:


 * 8 and 9 is the only pair of positive integer powers differing by 1.


 * If positive definite integral quadratic form represents integers 1-15, then it represents all positive integers.


 * Tarski gave axiomatization of identities involving only addition, multiplication and exponentiation. However, as proven by Wilkie, there are identities which cannot be derived from these axioms, as their proofs require notion of subtraction axioms did not provide.