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

1,2

Links

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A358457 A306235 A353441 * A322386 A309583 A327478

Adjacent sequences: A004613 A004614 A004615 * A004617 A004618 A004619

Keyword

nonn

Author

N. J. A. Sloane

Extensions

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

Status

approved