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 A097543 Sum_{k=1..n-1} J(2*n,k)*k^2, where J(i,j) is the Jacobi symbol. 1
 0, 1, 1, -8, 10, -24, 17, 84, 25, 24, 115, -144, 170, -224, 98, 32, 244, 654, 803, -560, 916, -616, -109, 96, -152, 312, 913, -1120, 2238, -1440, 2051, 5456, 1012, -272, 2438, -288, 1162, -2888, 2596, 96, 5864, 1008, 3315, -4048, 3840, -3680, -155, 576, 1713, 16700, 8838, -5200, 3166 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Suggested by a formula in Petersson. REFERENCES H. Petersson, Modulfunktionen und Quadratische Formen, Springer-Verlag, 1982; p. 98. LINKS MATHEMATICA Table[Sum[JacobiSymbol[2n, k] k^2, {k, 1, n - 1}], {n, 50}] (* Alonso del Arte, Oct 24 2014 *) PROG (PARI) a(n)=sum(k=1, n-1, kronecker(2*n, k)*k^2); \\ Joerg Arndt, Oct 25 2014 CROSSREFS Cf. A097541-A097544. Sequence in context: A032488 A102844 A303199 * A088034 A182405 A182366 Adjacent sequences:  A097540 A097541 A097542 * A097544 A097545 A097546 KEYWORD sign AUTHOR N. J. A. Sloane, Aug 27 2004 STATUS approved

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Last modified May 13 00:11 EDT 2021. Contains 343829 sequences. (Running on oeis4.)