A141894 Primes congruent to 13 mod 21.

13, 97, 139, 181, 223, 307, 349, 433, 601, 643, 727, 769, 811, 853, 937, 1021, 1063, 1231, 1399, 1483, 1567, 1609, 1693, 1777, 1861, 1987, 2029, 2113, 2239, 2281, 2617, 2659, 2953, 3037, 3079, 3121, 3163, 3331, 3373, 3457, 3499, 3541, 3583, 3709, 3793, 3877

Offset: 1

Author

N. J. A. Sloane, Jul 11 2008

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A124826.

Programs

Magma

[ p: p in PrimesUpTo(5000) | p mod 21 eq 13 ]; // Vincenzo Librandi, Apr 05 2011

Mathematica

Select[Range[13,5000,21],PrimeQ] (* Vladimir Joseph Stephan Orlovsky, Apr 04 2011 *)

PARI

is(n)=isprime(n) && n%21==13 \\ Charles R Greathouse IV, Jul 01 2016

Formula

a(n) ~ 12n log n. - Charles R Greathouse IV, Jul 01 2016