Number of primes <= n, if 1 is counted as a prime.

Terms

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