A039507 Number of odd non-cluster primes less than 10^n.

0, 1, 68, 808, 7784, 70210, 624561, 5559246, 49787726, 449315793, 4086143347, 37425892724, 345004813781

Offset

1,3

Comments

The Blecksmith paper gives incorrect values of a(n) for n>8. - T. D. Noe, Jul 21 2006

Links

Table of n, a(n) for n=1..13.

Richard Blecksmith, Paul Erdős and J. L. Selfridge, Cluster Primes, Amer. Math. Monthly, 106 (1999), 43-48.

Eric Weisstein's World of Mathematics, Cluster Prime.

Wikipedia, Cluster prime.

Index entries for sequences related to numbers of primes in various ranges

Formula

a(n) = A006880(n) - A039506(n) - 1. - T. D. Noe, Jul 21 2006

Crossrefs

Cf. A038133, A038134, A039506.

Sequence in context: A166398 A200876 A386747 * A250144 A250338 A223374

Adjacent sequences: A039504 A039505 A039506 * A039508 A039509 A039510

Keyword

nonn,more

Author

Christian G. Bower, Feb 15 1999

Extensions

Corrected by T. D. Noe, Jul 21 2006

Status

approved