a(1) = 3; a(n+1) = a(n)-th composite.

Terms

a(0) =3a(1) =8a(2) =15a(3) =25a(4) =38a(5) =55a(6) =77a(7) =105a(8) =140a(9) =183a(10) =235a(11) =298a(12) =372a(13) =462a(14) =566a(15) =692a(16) =838a(17) =1007a(18) =1205a(19) =1432a(20) =1698a(21) =2002a(22) =2352a(23) =2755a(24) =3210a(25) =3731a(26) =4322a(27) =4990a(28) =5747a(29) =6601