Numbers that are divisible by exactly 2 different primes; numbers n with omega(n) = A001221(n) = 2.

Terms

a(0) =6a(1) =10a(2) =12a(3) =14a(4) =15a(5) =18a(6) =20a(7) =21a(8) =22a(9) =24a(10) =26a(11) =28a(12) =33a(13) =34a(14) =35a(15) =36a(16) =38a(17) =39a(18) =40a(19) =44a(20) =45a(21) =46a(22) =48a(23) =50a(24) =51a(25) =52a(26) =54a(27) =55a(28) =56a(29) =57