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Numbers k such that (prime(k) mod 5) is even.
3

%I #18 Apr 21 2021 04:25:56

%S 1,3,4,7,8,10,12,15,17,19,22,24,25,28,29,31,33,34,35,37,39,41,45,46,

%T 49,50,52,55,57,59,63,66,68,69,70,72,73,75,77,78,80,81,85,87,88,91,92,

%U 93,95,97,101,102,104,106,107,109,111,113,114,118,120,123,127

%N Numbers k such that (prime(k) mod 5) is even.

%C Complement of A244737.

%H Clark Kimberling, <a href="/A244736/b244736.txt">Table of n, a(n) for n = 1..1000</a>

%e k prime(k) mod 5 mod 2

%e 1 2 2 0

%e 2 3 3 1

%e 3 5 0 0

%e 4 7 2 0

%e 5 11 1 1

%e 6 13 3 1

%p A244736:=n->`if`(type(ithprime(n) mod 5, even), n, NULL): seq(A244736(n), n=1..150); # _Wesley Ivan Hurt_, Jul 06 2014

%t z = 300; u = Mod[Table[Mod[Prime[n], 5], {n, 1, z}], 2] (* A244735 *)

%t Flatten[Position[u, 0]] (* A244736 *)

%t Flatten[Position[u, 1]] (* A244737 *)

%t Position[Mod[Prime[Range[130]],5],_?EvenQ]//Flatten (* _Harvey P. Dale_, Jan 28 2019 *)

%Y Cf. A039703, A244735, A244737.

%K nonn,easy

%O 1,2

%A _Clark Kimberling_, Jul 05 2014