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A039506 Number of cluster primes less than 10^n. 6
3, 23, 99, 420, 1807, 8287, 40017, 202208, 1059807, 5736717, 31911465, 182019293, 1060723057 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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.

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

CROSSREFS

Cf. A038133, A038134, A039507.

Cf. A121044, A121045 (cluster primes near 10^n).

Sequence in context: A301580 A112459 A197303 * A196970 A197557 A225671

Adjacent sequences:  A039503 A039504 A039505 * A039507 A039508 A039509

KEYWORD

nonn,more

AUTHOR

Christian G. Bower, Feb 15 1999

EXTENSIONS

Corrected by T. D. Noe, Jul 21 2006

STATUS

approved

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Last modified May 11 19:29 EDT 2021. Contains 343808 sequences. (Running on oeis4.)