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A158090
Period 9: repeat [0, 6, 0, 6, 0, 0, 3, 3, 0].
3
0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0, 3, 3, 0, 0, 6, 0, 6, 0, 0
OFFSET
0,2
COMMENTS
Also the continued fraction expansion of 6+sqrt(3970)/10 (dropping a(0)).
Also the decimal expansion of 6733370/111111111.
FORMULA
a(n) = ( A061037(n)*A061037(n+1) ) mod 9.
a(n) = a(n-9). G.f.: -3*x*(2+2*x^2+x^5+x^6)/((x-1)*(1+x+x^2)*(x^6+x^3+1)).
CROSSREFS
KEYWORD
nonn,easy,less
AUTHOR
Paul Curtz, Mar 12 2009
EXTENSIONS
A-number in the formula corrected by R. J. Mathar, Sep 11 2009
STATUS
approved