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Number of primes of the form 7k+3 less than 10^n.
5

%I #17 May 29 2019 07:46:56

%S 1,5,30,209,1613,13105,110815,960213,8475123,75843438,686338138,

%T 6267994788,57677618350,534157031248

%N Number of primes of the form 7k+3 less than 10^n.

%C Computed by _T. D. Noe_, Dec 19 2003

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ModularPrimeCountingFunction.html">Modular Prime Counting Function</a>

%t p = Select[Table[7 i + 3, {i, 0, 10^7}], PrimeQ[#] &]; Table[Count[p, x_ /; x < 10^n], {n, 7}] (* _Robert Price_, May 28 2019 *)

%Y Cf. A091120, A091121, A091123, A091124, A091125.

%K nonn,more

%O 1,2

%A _Eric W. Weisstein_, Dec 19 2003

%E a(10) from _Robert G. Wilson v_, Dec 22 2003

%E a(11)-a(14) from _Hiroaki Yamanouchi_, Oct 14 2014