A170826 1,2,3,8,5,36,7,64,81,100,11,144,13,196,225,256,17,324, %N A170826 a(n) = GCD(n^2, n!). %C A170826 If n is prime then a(n)=n else if n<>4 a(n)=n^2(due to The Fundamental Theorem of Arithmetic). ? Zak