a(n) = gcd(a(n-1),n-1)*a(n-1) + d(n-1) if a(n-1) is not divisible by 2, otherwise a(n) = a(n-1)/2, where gcd denotes common divisor, d(n) is number of divisors of n.

A133904

a(n) = gcd(a(n-1),n-1)*a(n-1) + d(n-1) if a(n-1) is not divisible by 2, otherwise a(n) = a(n-1)/2, where gcd denotes common divisor, d(n) is number of divisors of n.