Numbers k such that if p_1,p_2,...,p_m, m>1, are the prime factors of k, then there is some b>0 such that k = Sum_{i=1..m} b^(p_i).

A058040

Numbers k such that if p_1,p_2,...,p_m, m>1, are the prime factors of k, then there is some b>0 such that k = Sum_{i=1..m} b^(p_i).