4414201

Appears in sequences

• Smallest nontrivial extension of n-th square which is a square not ending 00.at n=20A030688
• Least number x such that gcd(phi(x), sigma(x)) = n.at n=18A073815
• Smallest number m such that GCD(a+b,a-b) = n, where a = sigma(m) and b = phi(m).at n=18A077102
• Least x=a(n) such that product of common prime-divisors [without multiplicity] of sigma(x) and phi(x) equals n; or 0 if n is not a squarefree number or if no such x exists. Among indices n only squarefree numbers arise because multiplicity of prime factors is ignored.at n=18A082057
• a(n) = A129967(n) with digits reversed.at n=42A129970