A091117 Number of primes of the form 5k+2 less than 10^n.

2, 7, 47, 309, 2412, 19622, 166212, 1440496, 12712315, 113764040, 1029518338, 9401997001, 86516367791, 801235612995, 7461142817662, 69809586085288, 655889291466274, 6184988574866753, 58514406980464530

Offset

1,1

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.

Crossrefs

Cf. A045380.

Sequence in context: A386157 A386047 A385784 * A056854 A330149 A117141

Adjacent sequences: A091114 A091115 A091116 * A091118 A091119 A091120

Keyword

nonn,more

Author

Eric W. Weisstein, Dec 19 2003

Extensions

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

a(11)-a(12) from Amiram Eldar, Apr 12 2022

a(13)-a(19) from Benjamin Chaffin, Jun 02 2026

Status

approved