A142244 Primes congruent to 23 mod 42.

23, 107, 149, 191, 233, 317, 359, 401, 443, 569, 653, 821, 863, 947, 1031, 1283, 1367, 1409, 1451, 1493, 1619, 1787, 1871, 1913, 1997, 2039, 2081, 2207, 2333, 2417, 2459, 2543, 2711, 2753, 2837, 2879, 2963, 3089, 3257, 3299, 3467, 3593, 3677, 3719, 3761

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.

Programs

Magma

[p: p in PrimesUpTo(4000) | p mod 42 eq 23 ]; // Vincenzo Librandi, Aug 24 2012

Mathematica

Select[Prime[Range[1500]],MemberQ[{23},Mod[#,42]]&] (* Vincenzo Librandi, Aug 24 2012 *)
Select[Range[23,4000,42],PrimeQ] (* Harvey P. Dale, Dec 18 2013 *)

PARI

is(n)=isprime(n) && n%42==23 \\ Charles R Greathouse IV, Jul 02 2016

Formula

a(n) ~ 12n log n. - Charles R Greathouse IV, Jul 02 2016