Here it is a problem to be solve: Solve the diophantine equation Sdf(x)=p, where p is a prime, while Sdf(n) is the Smarandache double factorial function, i.e. Sdf(n) is the smallest integer such that Sdf(n)!! is divisible by n. Here m!! is the double factorial, m!!=m(m-2)(m-4)... .