47140601domain: NAppears in sequencesa(n) = F(n)/Product_{p=primes} F(p^(m_{n,p})), where p^(m_{n,p}) is highest power of p dividing n, m= nonnegative integer and F(k) is the k-th Fibonacci number.at n=51A113196a(n) = (1/3)*(Lucas(3*n) - Lucas(n)).at n=12A273622