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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
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: A136717 A261685 A136716 * A061930 A209691 A221683
KEYWORD
easy,sign
AUTHOR
Paul Barry, Apr 05 2006
STATUS
approved