A142152 Primes congruent to 21 mod 38.

59, 97, 173, 211, 401, 439, 743, 857, 971, 1009, 1123, 1237, 1427, 1579, 1693, 1997, 2111, 2339, 2377, 2719, 2833, 2909, 3023, 3061, 3137, 3251, 3517, 3593, 3631, 3821, 4049, 4201, 4391, 4657, 4733, 4999, 5113, 5189, 5227, 5303, 5417, 5531, 5569, 5683, 5987

Offset: 1

Author

N. J. A. Sloane, Jul 11 2008

Keywords

• nonn
• easy

Links

• Enrique Pérez Herrero, Table of n, a(n) for n = 1..2500

Crossrefs

Cf. A000040.

Programs

Magma

[p: p in PrimesUpTo(7000) | p mod 38 eq 21 ]; // Vincenzo Librandi, Aug 19 2012

Mathematica

isA142152[n_]:=(Mod[n,38]==21)&&(PrimeQ[n])
Select[Prime[Range[1000]], Mod[#,38]==21&]
Select[Range[21,6000,38],PrimeQ] (* Harvey P. Dale, Nov 06 2019 *)

PARI

is(n)=isprime(n) && n%38==21 \\ Charles R Greathouse IV, Jul 02 2016

Formula

a(n) ~ 18n log n. - Charles R Greathouse IV, Jul 02 2016