A055728 Number of prime lucky numbers <10^n.

0, 2, 9, 43, 211, 1300, 8616, 62446, 469146, 3656784, 29285501, 239911086

Offset

0,2

Links

Table of n, a(n) for n=0..11.

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

Example

a(2) = 9 since there are 9 prime numbers in the lucky number sequence A000959 that are less than 10^2 (3, 7, 13, 31, 37, 43, 67, 73, and 79).

Mathematica

lst = Range[1, 10^8, 2]; i = 2; While[ i <= (len = Length@lst) && (k = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++ ]; Table[Length@ Select[lst, PrimeQ@# && # < 10^n &], {n, 0, 8}] (* Robert G. Wilson v, May 12 2006 *)

Crossrefs

Cf. A031157, A000959, A000040.

Sequence in context: A217666 A002310 A309986 * A006795 A055824 A334680

Adjacent sequences: A055725 A055726 A055727 * A055729 A055730 A055731

Keyword

nonn,more

Author

Robert G. Wilson v, Jun 09 2000

Extensions

a(7)-a(8) from Robert G. Wilson v, May 12 2006

a(9) from Donovan Johnson, Jul 06 2010

a(10) from Kevin P. Thompson, Nov 22 2021

a(11) from Dana Jacobsen, Mar 08 2023

Status

approved