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A097541
Sum_{k=1..n-1} J(2*n,k)*k, where J(i,j) is the Jacobi symbol.
3
0, 1, 1, -2, 4, -4, 3, 16, 3, 0, 15, -12, 16, -16, 10, 0, 24, 54, 51, -28, 56, -28, 1, 0, -10, 0, 25, -40, 96, -48, 85, 256, 52, 0, 94, -8, 28, -76, 88, 0, 196, 0, 71, -92, 60, -80, 35, 0, 49, 500, 206, -100, 76, -4, 176, 0, 36, 0, 317, -136, 344, -160, 14, 0, 212, 0, 91, -184, 416, -152, 205, 864, 156
OFFSET
1,4
COMMENTS
Suggested by a formula in Petersson.
REFERENCES
H. Petersson, Modulfunktionen und Quadratische Formen, Springer-Verlag, 1982; p. 98.
MAPLE
with(numtheory); J:=jacobi; f:=proc(n) add( J(n, k)*k, k=1..(n/2-1)); end;
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Aug 27 2004
STATUS
approved