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 A151763 If n is a prime == 1 mod 4 then a(n) = 1, if n is a prime == 3 mod 4 then a(n) = -1, otherwise a(n) = 0. 8

%I

%S 0,0,-1,0,1,0,-1,0,0,0,-1,0,1,0,0,0,1,0,-1,0,0,0,-1,0,0,0,0,0,1,0,-1,

%T 0,0,0,0,0,1,0,0,0,1,0,-1,0,0,0,-1,0,0,0,0,0,1,0,0,0,0,0,-1,0,1,0,0,0,

%U 0,0,-1,0,0,0,-1,0,1,0,0,0,0,0,-1,0,0,0,-1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,-1,0,0

%N If n is a prime == 1 mod 4 then a(n) = 1, if n is a prime == 3 mod 4 then a(n) = -1, otherwise a(n) = 0.

%C a(A002145(n)) = -1; a(A065090(n)) = 0; a(A002144(n)) = 1. [_Reinhard Zumkeller_, Oct 06 2011]

%D N. Katz, Lang-Trotter revisited, Bull. Amer. Math. Soc., 46 (2009), 413-457.

%H _Reinhard Zumkeller_, <a href="/A151763/b151763.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = (2 - n mod 4) * A010051(n).

%o a151763 n | even n = 0

%o | a010051 n == 1 = 2 - n `mod` 4

%o | otherwise = 0

%o -- _Reinhard Zumkeller_, Oct 06 2011

%Y Cf. A0792600, A0792601.

%K sign

%O 1,1

%A _N. J. A. Sloane_, Jun 22 2009

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