A045457 Primes congruent to {0, 4} mod 5.

5, 19, 29, 59, 79, 89, 109, 139, 149, 179, 199, 229, 239, 269, 349, 359, 379, 389, 409, 419, 439, 449, 479, 499, 509, 569, 599, 619, 659, 709, 719, 739, 769, 809, 829, 839, 859, 919, 929, 1009, 1019, 1039, 1049, 1069, 1109, 1129, 1229, 1249, 1259, 1279

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

Being a subset of A141158, this is also a subset of the primes of form x^2 - 5*y^2. - Tito Piezas III, Dec 28 2008

Apparently primes p such that 5 | tau(p), where Ramanujan's tau is A000594. - Charles R Greathouse IV, Jul 08 2013

Links

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

Crossrefs

Same as A030433 prefixed with 5.

Cf. A000040.

Programs

Magma

[ p: p in PrimesUpTo(1300) | p mod 5 in {0, 4} ]; // Vincenzo Librandi, Aug 13 2012

Mathematica

Select[Prime@Range[210], MemberQ[{0, 4}, Mod[ #, 5]] &] (* Ray Chandler, Nov 07 2006 *)

PARI

is(n)=n==5 || (n%5==4 && isprime(n)) \\ Charles R Greathouse IV, Jul 08 2013

Extensions

Extended by Ray Chandler, Nov 07 2006