A086688 Number of primes < prime(n)^3.

4, 9, 30, 68, 217, 327, 656, 882, 1457, 2707, 3228, 5194, 6850, 7789, 9916, 13746, 18411, 20179, 26062, 30597, 32984, 40991, 46959, 56924, 72217, 80725, 85182, 94695, 99669, 110127, 152280, 165951, 187910, 195660, 237427, 246434, 274614

Offset: 1

Author

Cino Hilliard, Jul 28 2003

Keywords

• easy
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000720, A030078, A038098.

Programs

Mathematica

a[n_] := PrimePi[Prime[n]^3]; Array[a, 50] (* Amiram Eldar, Sep 06 2024 *)

PARI

a(n) = primepi(prime(n)^3); \\ Michel Marcus, Sep 18 2023

Formula

a(n) = A038098(prime(n)). - R. J. Mathar, Sep 15 2012

a(n) = A000720(A030078(n)). - Michel Marcus, Sep 18 2023