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

Offset: 1

Author

Labos Elemer, Oct 29 2001

Keywords

• easy
• nonn

Links

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

Crossrefs

Cf. A000040, A000720.

Programs

Mathematica

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

PARI

a(n) = { primepi(prime(n) - n) } \\ Harry J. Smith, Oct 16 2009

Formula

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