a(n) = prime(n) - (n-1).

Terms

a(0) =2a(1) =2a(2) =3a(3) =4a(4) =7a(5) =8a(6) =11a(7) =12a(8) =15a(9) =20a(10) =21a(11) =26a(12) =29a(13) =30a(14) =33a(15) =38a(16) =43a(17) =44a(18) =49a(19) =52a(20) =53a(21) =58a(22) =61a(23) =66a(24) =73a(25) =76a(26) =77a(27) =80a(28) =81a(29) =84