A091124 Number of primes of the form 7k+5 less than 10^n.

1, 5, 29, 211, 1604, 13105, 110787, 960379, 8474630, 75842174, 686346250, 6267992446, 57677618443, 534157056416, 4974095211561, 46539725090285, 437259525194535, 4123325715561080, 39009611235251818

Offset

1,2

Comments

Computed by T. D. Noe, Dec 19 2003.

Links

Table of n, a(n) for n=1..19.

Eric Weisstein's World of Mathematics, Modular Prime Counting Function

Mathematica

p = Select[Table[7 i + 5, {i, 0, 10^7}], PrimeQ[#] &]; Table[Count[p, x_ /; x < 10^n], {n, 7}] (* Robert Price, May 28 2019 *)

Crossrefs

Cf. A091120, A091121, A091122, A091123, A091125.

Sequence in context: A103213 A057588 A030522 * A121143 A027048 A356408

Adjacent sequences: A091121 A091122 A091123 * A091125 A091126 A091127

Keyword

nonn,more,changed

Author

Eric W. Weisstein, Dec 19 2003

Extensions

a(10) from Robert G. Wilson v, Dec 22 2003

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

a(15)-a(19) from Benjamin Chaffin, Jun 02 2026

a(19) corrected by Benjamin Chaffin, Jul 08 2026

Status

approved