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URL: https://oeis.org/A131969

⇱ A131969 - OEIS

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A131969
First differences of A020806.
1
3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6, 3, -2, 6, -3, 2, -6
OFFSET
0,1
FORMULA
a(n)=11*(-1)^n/3-2*A010892(n)/3+7*A010892(n-1)/3, n>0. a(n+6)=a(n). G.f.: (3-2x+6x^2)/((1+x)(1-x+x^2)). [From R. J. Mathar, Oct 24 2008]
CROSSREFS
Sequence in context: A389793 A263353 A248945 * A058971 A186204 A137324
KEYWORD
sign
AUTHOR
Paul Curtz, Oct 06 2007
STATUS
approved