A004616 Divisible only by primes congruent to 2 mod 5.

1, 2, 4, 7, 8, 14, 16, 17, 28, 32, 34, 37, 47, 49, 56, 64, 67, 68, 74, 94, 97, 98, 107, 112, 119, 127, 128, 134, 136, 137, 148, 157, 167, 188, 194, 196, 197, 214, 224, 227, 238, 254, 256, 257, 259, 268, 272, 274

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Links

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

Crossrefs

Cf. A045380 (primes congruent to 2 mod 5).

Programs

Magma

[n: n in [1..300] | forall{d: d in PrimeDivisors(n) | d mod 5 eq 2}]; // Bruno Berselli, Aug 11 2012

Mathematica

ok[1] = True; ok[n_] := And@@ (Mod[#, 5] == 2 &)/@ FactorInteger[n][[All,1]]; Select[Range[2000],ok] (* Vincenzo Librandi, Aug 11 2012 *)

Extensions

Offset changed from 0 to 1 by Vincenzo Librandi, Aug 20 2012