a(n) = prime(n)-n, the number of nonprimes less than prime(n).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =7a(6) =10a(7) =11a(8) =14a(9) =19a(10) =20a(11) =25a(12) =28a(13) =29a(14) =32a(15) =37a(16) =42a(17) =43a(18) =48a(19) =51a(20) =52a(21) =57a(22) =60a(23) =65a(24) =72a(25) =75a(26) =76a(27) =79a(28) =80a(29) =83