A065328 - OEIS

A065328

a(n) is the number of primes less than or equal to prime(n) - n.

0, 0, 1, 2, 3, 4, 4, 5, 6, 8, 8, 9, 9, 10, 11, 12, 13, 14, 15, 15, 15, 16, 17, 18, 20, 21, 21, 22, 22, 23, 24, 25, 27, 27, 30, 30, 30, 30, 31, 32, 33, 34, 34, 35, 36, 36, 38, 40, 40, 41, 42, 42, 42, 45, 46, 46, 47, 47, 47, 47, 47, 50, 53, 53, 53, 54, 56, 57, 59, 59, 60, 61, 62

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A000720(A000040(n) - A000027(n)).

MATHEMATICA

Table[PrimePi[Prime[n]-n], {n, 80}] (* Harvey P. Dale, Oct 02 2013 *)

PROG

(PARI) { for (n=1, 1000, write("b065328.txt", n, " ", primepi(prime(n) - n)) ) } \\ Harry J. Smith, Oct 16 2009

CROSSREFS