A038801 Number of primes less than 10n.

4, 8, 10, 12, 15, 17, 19, 22, 24, 25, 29, 30, 31, 34, 35, 37, 39, 41, 42, 46, 46, 47, 50, 52, 53, 55, 57, 59, 61, 62, 63, 66, 66, 68, 70, 72, 73, 75, 77, 78, 80, 81, 82, 85, 87, 88, 91, 92, 93, 95, 97, 97, 99, 99, 101, 102, 104, 106, 107, 109, 111, 114, 114, 115, 118, 120

Offset: 1

Author

Jeff Burch

Keywords

• nonn

Comments

For almost all n, that is for a set of density 1, a(n) = a(n-1), and in all cases a(n) <= a(n-1) + 4. - Charles R Greathouse IV, Aug 27 2014

Links

• Robert G. Wilson v, Table of n, a(n) for n = 1..10000
• Andrew R. Booker, The Nth Prime Page
• Thomas R. Nicely, Some Results of Computational Research in Prime Numbers [See local copy in A007053]
• Tomás Oliveira e Silva, Tables of values of pi(x) and of pi2(x)

Crossrefs

Cf. A028505, A038812, A038813, A038814, A038815, A038816, A038817, A038818, A038819, A038820, A038821, A080122, A080123, A080124, A080125, A080126, A080127, A080128, A080129.

Programs

Mathematica

Table[ PrimePi[ n*10 ], {n, 1, 66}] (* Robert G. Wilson v *)

PARI

a(n)=primepi(10*n) \\ Charles R Greathouse IV, Aug 27 2014

Extensions

Edited and corrected by Robert G. Wilson v, Jan 29 2003