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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. 10
 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, 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, 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(A002145(n)) = -1; a(A065090(n)) = 0; a(A002144(n)) = 1. [Reinhard Zumkeller, Oct 06 2011] LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 N. Katz, Lang-Trotter revisited, Bull. Amer. Math. Soc., 46 (2009), 413-457. FORMULA a(n) = (2 - n mod 4) * A010051(n). MAPLE a:= proc(n) if n::odd and isprime(n) then 2 - (n mod 4) else 0 fi end proc: seq(a(n), n=1..100); # Robert Israel, Aug 22 2014 MATHEMATICA a[n_] := Which[!PrimeQ[n], 0, m = Mod[n, 4]; m == 1, 1, m == 3, -1, True, 0]; Array[a, 105] (* Jean-François Alcover, Dec 03 2016 *) PROG (Haskell) a151763 n | even n         = 0           | a010051 n == 1 = 2 - n `mod` 4           | otherwise      = 0 -- Reinhard Zumkeller, Oct 06 2011 CROSSREFS Cf. A079260, A079261. Cf. A066520 (partial sums). Sequence in context: A072629 A164292 A257531 * A324908 A022925 A327211 Adjacent sequences:  A151760 A151761 A151762 * A151764 A151765 A151766 KEYWORD sign AUTHOR N. J. A. Sloane, Jun 22 2009 STATUS approved

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Last modified October 22 19:53 EDT 2019. Contains 328319 sequences. (Running on oeis4.)