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A244797 Number of moduli m such that (prime(n) mod m) = 2. 4

%I

%S 0,0,1,1,2,1,3,1,3,3,1,3,3,1,5,3,3,1,3,3,1,3,4,3,3,5,1,7,1,3,3,3,7,1,

%T 5,1,3,3,7,5,3,1,7,1,7,1,3,3,8,1,7,3,1,3,7,5,3,1,5,5,1,3,3,3,1,11,3,3,

%U 7,1,7,7,3,3,3,3,5,3,7,3,3,1,7,1,3,8

%N Number of moduli m such that (prime(n) mod m) = 2.

%C Except for the initial 0,0, this is column 2 of the array at A244740.

%H Clark Kimberling, <a href="/A244797/b244797.txt">Table of n, a(n) for n = 1..1000</a>

%e prime(5) = 11 = (2 mod m) for m = 3, 9 so that a(5) = 2.

%t z = 300; f[n_, m_] := If[Mod[Prime[n], m] == 2, 1, 0];

%t t = Table[f[n, m], {n, 1, z}, {m, 1, Prime[n]}];

%t Table[Count[t[[k]], 1], {k, 1, z}] (* A244797 *)

%Y Cf. A244740, A244796, A244798.

%K nonn,easy

%O 1,5

%A _Clark Kimberling_, Jul 06 2014

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Last modified August 9 16:39 EDT 2022. Contains 356026 sequences. (Running on oeis4.)