A141966 Primes congruent to 3 mod 28.

3, 31, 59, 199, 227, 283, 311, 367, 479, 563, 619, 647, 787, 983, 1039, 1123, 1151, 1291, 1319, 1459, 1487, 1543, 1571, 1627, 1823, 1879, 1907, 2131, 2243, 2383, 2411, 2467, 2551, 2579, 2663, 2719, 2803, 2887, 2971, 2999, 3083, 3167, 3251, 3307, 3391, 3559

Offset

1,1

Comments

Also primes of the form 7*x^2 - y^2 (see Uspensky and Heaslet). - Stefano Spezia, Jun 29 2026

References

J. V. Uspensky and M. A. Heaslet, Elementary Number Theory, McGraw-Hill, NY, 1939, Exercise n. 2 at p. 368.

Links

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

Formula

a(n) ~ 12n log n. - Charles R Greathouse IV, Jul 03 2016

Mathematica

Select[Prime[Range[500]], MemberQ[{3}, Mod[#, 28]] &] (* Vincenzo Librandi, Aug 16 2012 *)
(* Alternative: *)
Select[Range[3, 4000, 28], PrimeQ] (* Harvey P. Dale, Jul 07 2016 *)

Prog

(Magma) [p: p in PrimesUpTo(5000) | p mod 28 eq 3 ]; // Vincenzo Librandi, Aug 16 2012
(PARI) is(n)=isprime(n) && n%28==3 \\ Charles R Greathouse IV, Jul 03 2016

Crossrefs

Cf. A000040.

Sequence in context: A290401 A341928 A238663 * A050833 A041207 A133203

Adjacent sequences: A141963 A141964 A141965 * A141967 A141968 A141969

Keyword

nonn,easy

Author

N. J. A. Sloane, Jul 11 2008

Status

approved