4680600domain: NAppears in sequencesa(n) = sigma(n)*Pell(n), where sigma(n) = A000203(n), the sum of divisors of n.at n=14A204271a(n) = Pell(n)*A034896(n) for n >= 1, with a(0)=1, where A034896 lists the number of solutions to a^2 + b^2 + 3*c^2 + 3*d^2 = n.at n=15A209451