A086692 - OEIS

A086692

Number of primes < 3^prime(n).

4, 9, 53, 327, 16097, 120739, 7332159, 58648288, 3886548158, 2226457080707, 18703411700669, 11364488265762429, 828569015819923142, 7102411822168379213, 525323427853694627277

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OFFSET

2,1

LINKS

Table of n, a(n) for n=2..16.

FORMULA

a(n) = A055729(prime(n)). - R. J. Mathar, Sep 15 2012

EXAMPLE

There are 4 primes < 3^2

MATHEMATICA

Table[PrimePi[3^Prime[n]], {n, 9}] (* Michael De Vlieger, Mar 20 2015 *)

PROG

(PARI) primesless3p(n) = /* primes less than 3^p */ { forprime(x=2, n, y=primepi(3^x); print1(y", "); ); print()}

CROSSREFS

Cf. A055729.

Sequence in context: A370579 A368634 A009276 * A242036 A069507 A219894

Adjacent sequences: A086689 A086690 A086691 * A086693 A086694 A086695

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, Jul 28 2003

EXTENSIONS

a(10)-a(16) added by David Baugh, Mar 17 2015

STATUS

approved