3 problems
Congruence twin conjecture. Suppose that the dimension is odd and . Then every vector of length has a twin.
Odd-dimensional twin conjecture. Suppose that the dimension is odd. Then every non-odd vector has a twin.
Squarefree twin-complete numbers conjecture. The complete list of squarefree numbers that can be written as a sum of at most two positive squares, but not as a sum of three positiv…