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

1,4

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.

Links

Table of n, a(n) for n=1..100.

Prog

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

Crossrefs

Cf. A110835, A000578, A007531, A034262.

Sequence in context: A317086 A131376 A025840 * A029284 A123275 A112544

Adjacent sequences: A188539 A188540 A188541 * A188543 A188544 A188545

Keyword

nonn

Author

Franklin T. Adams-Watters, Apr 07 2011

Status

approved