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URL: https://oeis.org/A091166

⇱ A091166 - OEIS

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A091166
Number of primes of the form 30k + 7 less than 10^n.
8
1, 4, 24, 155, 1200, 9812, 83104, 720270, 6356475, 56881453, 514763437, 4701002681, 43258188715
OFFSET
1,2
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: A003288 A390358 A178879 * A078108 A210474 A344735
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Jan 12 2004
EXTENSIONS
a(11)-a(13) from Hiroaki Yamanouchi, Oct 14 2014
STATUS
approved