Numbers with 4 divisors.

Terms

a(0) =6a(1) =8a(2) =10a(3) =14a(4) =15a(5) =21a(6) =22a(7) =26a(8) =27a(9) =33a(10) =34a(11) =35a(12) =38a(13) =39a(14) =46a(15) =51a(16) =55a(17) =57a(18) =58a(19) =62a(20) =65a(21) =69a(22) =74a(23) =77a(24) =82a(25) =85a(26) =86a(27) =87a(28) =91a(29) =93