4753125domain: NAppears in sequencesa(n)^2 is a square composed of three '2 digit' overlapping subsquares.at n=7A048428Odd numbers of the form p^(1+4k) * r^2, where p is prime of the form 1+4m, k > 0, r > 1, and gcd(p,r) = 1.at n=15A386428