a(1) = 3; a(n+1) = a(n)-th nonprime, where nonprimes begin at 1.

Terms

a(0) =3a(1) =6a(2) =10a(3) =16a(4) =25a(5) =36a(6) =51a(7) =70a(8) =94a(9) =124a(10) =161a(11) =207a(12) =262a(13) =328a(14) =407a(15) =502a(16) =614a(17) =746a(18) =900a(19) =1080a(20) =1288a(21) =1529a(22) =1808a(23) =2127a(24) =2494a(25) =2915a(26) =3393a(27) =3939a(28) =4556a(29) =5253