A004618 Divisible only by primes congruent to 4 mod 5.

1, 19, 29, 59, 79, 89, 109, 139, 149, 179, 199, 229, 239, 269, 349, 359, 361, 379, 389, 409, 419, 439, 449, 479, 499, 509, 551, 569, 599, 619, 659, 709, 719, 739, 769, 809, 829, 839, 841, 859, 919, 929, 1009, 1019

Offset

1,2

Links

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

Mathematica

ok[1]=True; ok[n_]:=And@@(Mod[#, 5]==4&)/@FactorInteger[n][[All, 1]]; Select[Range[4000], ok] (* Vincenzo Librandi, Aug 20 2012 *)

Prog

(Magma) [n: n in [1..1100] | forall{d: d in PrimeDivisors(n) | d mod 5 eq 4}]; // Vincenzo Librandi, Aug 20 2012

Crossrefs

Sequence in context: A106093 A084666 A242265 * A030433 A242550 A141311

Adjacent sequences: A004615 A004616 A004617 * A004619 A004620 A004621

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved