A091116 Number of primes of the form 3k+2 less than 10^n.

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

Table of n, a(n) for n=1..15.

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

Cf. A003627, A091115, A091119.

Sequence in context: A074619 A162275 A092070 * A091099 A092849 A300429

Adjacent sequences: A091113 A091114 A091115 * A091117 A091118 A091119

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