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

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =-1a(4) =2a(5) =3a(6) =5a(7) =5a(8) =8a(9) =13a(10) =13a(11) =17a(12) =20a(13) =21a(14) =23a(15) =28a(16) =33a(17) =34a(18) =39a(19) =41a(20) =41a(21) =46a(22) =49a(23) =54a(24) =61a(25) =63a(26) =64a(27) =67a(28) =67a(29) =69