a(1) = 7; a(n+1) = a(n)-th nonprime, where nonprimes begin at 1.

Terms

a(0) =7a(1) =12a(2) =20a(3) =30a(4) =44a(5) =62a(6) =85a(7) =115a(8) =150a(9) =194a(10) =247a(11) =310a(12) =386a(13) =477a(14) =583a(15) =710a(16) =858a(17) =1030a(18) =1232a(19) =1464a(20) =1734a(21) =2043a(22) =2400a(23) =2809a(24) =3270a(25) =3798a(26) =4396a(27) =5073a(28) =5838a(29) =6702