a(n) = Sum_{i=0..n-1} (-1)^i * prime(n-i).

Terms

a(0) =0a(1) =2a(2) =1a(3) =4a(4) =3a(5) =8a(6) =5a(7) =12a(8) =7a(9) =16a(10) =13a(11) =18a(12) =19a(13) =22a(14) =21a(15) =26a(16) =27a(17) =32a(18) =29a(19) =38a(20) =33a(21) =40a(22) =39a(23) =44a(24) =45a(25) =52a(26) =49a(27) =54a(28) =53a(29) =56