a(n) = n-th prime + n-th nonprime.

Terms

a(0) =3a(1) =7a(2) =11a(3) =15a(4) =20a(5) =23a(6) =29a(7) =33a(8) =38a(9) =45a(10) =49a(11) =57a(12) =62a(13) =65a(14) =71a(15) =78a(16) =85a(17) =88a(18) =95a(19) =101a(20) =105a(21) =112a(22) =117a(23) =124a(24) =133a(25) =139a(26) =142a(27) =147a(28) =151a(29) =157