Semiprimes followed by successive gaps 4, 6, 9.

Terms

a(0) =8203a(1) =9703a(2) =18163a(3) =35823a(4) =72687a(5) =72847a(6) =75759a(7) =95695a(8) =97959a(9) =132879a(10) =177159a(11) =194127a(12) =198763a(13) =201099a(14) =210379a(15) =223807a(16) =226887a(17) =228043a(18) =299227a(19) =306283a(20) =344779a(21) =347527a(22) =351399a(23) =360763a(24) =403467a(25) =407107a(26) =454143a(27) =487927a(28) =506467a(29) =514927