A142650 Primes congruent to 23 mod 56.

23, 79, 191, 359, 751, 863, 919, 1031, 1087, 1367, 1423, 1759, 1871, 2039, 2207, 2543, 2711, 2767, 2879, 3271, 3607, 3719, 3943, 4111, 4391, 4447, 4783, 4951, 5119, 5231, 5399, 5623, 5791, 5903, 6911, 6967, 7079, 7247, 7583, 7639, 7919, 8087, 8311, 8423

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(10000) | p mod 56 eq 23 ]; // Vincenzo Librandi, Sep 01 2012

Mathematica

Select[Prime[Range[1100]],Mod[#,56]==23&] (* Harvey P. Dale, Jul 14 2011 *)
Select[Prime[Range[1300]], MemberQ[{23}, Mod[#, 56]] &] (* Vincenzo Librandi, Sep 01 2012 *)
Select[Range[23,8500,56],PrimeQ] (* Harvey P. Dale, Apr 13 2020 *)

PARI

is(n)=isprime(n) && n%56==23 \\ Charles R Greathouse IV, Jul 03 2016

Formula

a(n) ~ 24n log n. - Charles R Greathouse IV, Jul 03 2016