A142192 Primes congruent to 23 mod 40.

23, 103, 223, 263, 383, 463, 503, 743, 823, 863, 983, 1063, 1103, 1223, 1303, 1423, 1543, 1583, 1663, 1783, 1823, 2063, 2143, 2383, 2423, 2503, 2543, 2663, 2903, 3023, 3343, 3463, 3583, 3623, 3823, 3863, 3943, 4423, 4463, 4583, 4663, 4703, 4783, 4903, 4943

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(6000) | p mod 40 eq 23 ]; // Vincenzo Librandi, Aug 22 2012

Mathematica

Select[Prime[Range[2000]],MemberQ[{23},Mod[#,40]]&] (* Vincenzo Librandi, Aug 22 2012 *)
Select[Range[23,5000,40],PrimeQ] (* Harvey P. Dale, Apr 22 2018 *)

PARI

is(n)=isprime(n) && n%40==23 \\ Charles R Greathouse IV, Jul 02 2016

Formula

a(n) ~ 16n log n. - Charles R Greathouse IV, Jul 02 2016