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A325756

A number n belongs to the sequence if n = 1 or n is divisible by its prime shadow A181819(n) and the quotient n/A181819(n) also belongs to the sequence.

We define the prime shadow A181819(n) to be the product of primes indexed by the exponents in the prime factorization of n. For example, 90 = prime(1)*prime(2)^2*prime(3) has prime shadow prime(1)*prime(2)*prime(1) = 12.