0,3

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Table[n - PrimePi[n/2], {n, 0, 100}] (* Vincenzo Librandi, Feb 18 2017 *)

(MAGMA) [0, 1] cat [ n-#PrimesUpTo(n div 2): n in [2..90] ]; // Vincenzo Librandi, Feb 18 2017

(PARI) a(n)=n - primepi(n\2) \\ Charles R Greathouse IV, Feb 18 2017

Cf. A000720, A282028.

Sequence in context: A135671 A079420 A076895 * A029086 A070046 A130120

Adjacent sequences: A282026 A282027 A282028 * A282030 A282031 A282032

nonn

N. J. A. Sloane, Feb 17 2017

approved