Numbers k = p_i^e_i *...* p_r^e_r such that i/e_i +...+ r/e_r = 1 for e_i,..., e_r >= 1; p_i,..., p_r distinct prime numbers (A000040).

A388006

Numbers k = p_i^e_i *...* p_r^e_r such that i/e_i +...+ r/e_r = 1 for e_i,..., e_r >= 1; p_i,..., p_r distinct prime numbers (A000040).