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A004618 Divisible only by primes congruent to 4 mod 5. 4

%I

%S 1,19,29,59,79,89,109,139,149,179,199,229,239,269,349,359,361,379,389,

%T 409,419,439,449,479,499,509,551,569,599,619,659,709,719,739,769,809,

%U 829,839,841,859,919,929,1009,1019

%N Divisible only by primes congruent to 4 mod 5.

%H Vincenzo Librandi, <a href="/A004618/b004618.txt">Table of n, a(n) for n = 1..1000</a>

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

%o (MAGMA) [n: n in [1..1100] | forall{d: d in PrimeDivisors(n) | d mod 5 eq 4}]; // _Vincenzo Librandi_, Aug 20 2012

%K nonn,easy

%O 1,2

%A _N. J. A. Sloane_.

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Last modified December 3 22:32 EST 2021. Contains 349468 sequences. (Running on oeis4.)