Number of odd composite numbers less than n-th odd prime.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =2a(6) =2a(7) =3a(8) =5a(9) =5a(10) =7a(11) =8a(12) =8a(13) =9a(14) =11a(15) =13a(16) =13a(17) =15a(18) =16a(19) =16a(20) =18a(21) =19a(22) =21a(23) =24a(24) =25a(25) =25a(26) =26a(27) =26a(28) =27a(29) =33