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A091116
Number of primes of the form 3k+2 less than 10^n.
2
2, 13, 87, 617, 4807, 39266, 332384, 2880937, 25424820, 227529387, 2059036144, 18803978497, 173032844825, 1602471005227, 14922285950520
OFFSET
1,1
COMMENTS
Computed by T. D. Noe, Dec 19 2003.
LINKS
Eric Weisstein's World of Mathematics, Modular Prime Counting Function.
FORMULA
a(n) = A091119(n) + 1.
MATHEMATICA
p = Select[Table[3 i + 2, {i, 0, 10^7}], PrimeQ[#] &]; Table[Count[p, x_ /; x < 10^n], {n, 7}] (* Robert Price, May 29 2019 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Eric W. Weisstein, Dec 19 2003
EXTENSIONS
a(10) from Robert G. Wilson v, Dec 22 2003
a(11)-a(13) from Chai Wah Wu, Jul 01 2019
a(14)-a(15) added from the data at A091119 by Amiram Eldar, Apr 22 2022
STATUS
approved