A188542 Number of primes between n^3-n and n^3+n.

1, 1, 1, 2, 1, 1, 3, 1, 2, 3, 2, 3, 2, 4, 4, 4, 3, 5, 5, 4, 4, 7, 4, 4, 8, 7, 6, 5, 6, 5, 4, 6, 6, 5, 6, 9, 5, 5, 5, 7, 9, 7, 5, 7, 12, 8, 8, 12, 7, 8, 13, 10, 10, 9, 10, 7, 11, 11, 11, 6, 5, 11, 13, 12, 8, 8, 14, 9, 5, 7, 5, 14, 12, 13, 8, 11, 15, 15, 12, 11, 5, 11, 17, 14, 15, 15, 12, 15, 14, 16, 14, 17, 13, 15, 15, 12, 6, 17, 16, 14

Offset: 1

Author

Franklin T. Adams-Watters, Apr 07 2011

Keywords

• nonn

Comments

We include the end points in the range; this affects the value only for n=1.

Conjecture: the sequence contains no 0's. Verified up to n = 100000.

Crossrefs

Cf. A110835, A000578, A007531, A034262.

Programs

PARI

vector(100,m,sum(k=m^3-m,m^3+m,isprime(k)))