520801

Appears in sequences

• Nonprimes n such that Mod(n,4) == 1 and denominator(Fibonacci((n-1)/4)/n) = 1.at n=19A091982
• Frobenius pseudoprimes == 1,4 (mod 5) with respect to Fibonacci polynomial x^2 - x - 1.at n=33A319168
• a(n) = n! * Sum_{d|n} (n/d)! / d!.at n=5A354862