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A117946 a(3n)=0, a(3n+1)/a(1)=a(3n+2)/a(2)=A059151(n). 1
0, 1, -2, 0, 2, -4, 0, 1, -2, 0, 2, -4, 0, 4, -8, 0, 2, -4, 0, 1, -2, 0, 2, -4, 0, 1, -2, 0, 2, -4, 0, 4, -8, 0, 2, -4, 0, 4, -8, 0, 8, -16, 0, 4, -8, 0, 2, -4, 0, 4, -8, 0, 2, -4, 0, 1, -2, 0, 2, -4, 0, 1, -2, 0, 2, -4, 0, 4, -8, 0, 2, -4, 0, 1, -2, 0, 2, -4, 0, 1, -2, 0, 2, -4, 0, 4, -8, 0, 2, -4, 0, 4, -8, 0, 8, -16, 0, 4, -8 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

Second column of A117939.

FORMULA

a(n)=sum{k=0..n, L((n-j)/3)*L(C(n,k)/3)} where L(j/p) is the Legendre symbol of j and p.

CROSSREFS

Sequence in context: A185296 A136717 A136716 * A061930 A199335 A141660

Adjacent sequences:  A117943 A117944 A117945 * A117947 A117948 A117949

KEYWORD

easy,sign

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Apr 05 2006

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Last modified February 16 17:48 EST 2012. Contains 205939 sequences.