cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

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

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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

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