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Search: id:A117940
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A117940 a(0)=1,a(n)=a(3n)=a(3n+1)/3,a(3n+2)=0. +0
2
1, 3, 0, 3, 9, 0, 0, 0, 0, 3, 9, 0, 9, 27, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 9, 0, 9, 27, 0, 0, 0, 0, 9, 27, 0, 27, 81, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 9, 0, 9, 27, 0, 0, 0, 0, 9, 27, 0, 27, 81, 0, 0, 0, 0, 0, 0 (list; graph; listen)
OFFSET

0,2

COMMENT

a(n)=a(3n)/a(0)=a(3n+1)/a(1). a(n) mod 2=A039966(n). Row sums of A117939.

FORMULA

G.f.: Product{k>=0, 1+3x^(3^k)}; a(n)=sum{k=0..n, sum{j=0..n, L(C(n,j)/3)*L(C(n-j,k)/3)}} where L(j/p) is the Legendre symbol of j and p.

CROSSREFS

Sequence in context: A021771 A139214 A010030 this_sequence A099093 A137339 A132330

Adjacent sequences: A117937 A117938 A117939 this_sequence A117941 A117942 A117943

KEYWORD

easy,nonn

AUTHOR

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

page 1

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Last modified November 18 20:14 EST 2008. Contains 147244 sequences.


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