Number of primes < n^2.

Terms

a(0) =0a(1) =0a(2) =2a(3) =4a(4) =6a(5) =9a(6) =11a(7) =15a(8) =18a(9) =22a(10) =25a(11) =30a(12) =34a(13) =39a(14) =44a(15) =48a(16) =54a(17) =61a(18) =66a(19) =72a(20) =78a(21) =85a(22) =92a(23) =99a(24) =105a(25) =114a(26) =122a(27) =129a(28) =137a(29) =146