A091166 Number of primes of the form 30k + 7 less than 10^n.

1, 4, 24, 155, 1200, 9812, 83104, 720270, 6356475, 56881453, 514763437, 4701002681, 43258188715

Offset

1,2

Links

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

Mathematica

a[n_]:=Length[Select[Range[0, Floor[1/30*(-7+10^n)]], PrimeQ[30*#+7]&]]
a/@Range[1, 7] (* Julien Kluge, Sep 20 2016 *)

Crossrefs

Cf. A091165 + A091166 + A091167 + A091168 + A091169 + A091170 + A091171 + A091172 +3 (for 2, 3 & 5) = A006880.

Sequence in context: A192927 A003288 A178879 * A078108 A210474 A344735

Adjacent sequences: A091163 A091164 A091165 * A091167 A091168 A091169

Keyword

nonn,more

Author

Robert G. Wilson v, Jan 12 2004

Extensions

a(11)-a(13) from Hiroaki Yamanouchi, Oct 14 2014

Status

approved