Odd squarefree composite numbers.

Terms

a(0) =15a(1) =21a(2) =33a(3) =35a(4) =39a(5) =51a(6) =55a(7) =57a(8) =65a(9) =69a(10) =77a(11) =85a(12) =87a(13) =91a(14) =93a(15) =95a(16) =105a(17) =111a(18) =115a(19) =119a(20) =123a(21) =129a(22) =133a(23) =141a(24) =143a(25) =145a(26) =155a(27) =159a(28) =161a(29) =165