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A131707
Period 12: repeat 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9 .
6
1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9, 1, 1, 3, 7, 7, 1, 9, 9, 7
OFFSET
0,3
COMMENTS
Also the decimal expansion of 1023949/9000009. [R. J. Mathar, Feb 07 2009]
FORMULA
a(n) = A001333(n) mod 10. - Paul Curtz, Apr 08 2008
G.f.: (1+2x^2+4x^3-6x^5+9x^6)/((1-x)(1+x^2)(1-x^2+x^4)). a(n)=a(n-1)-a(n-6)+a(n-7). [R. J. Mathar, Feb 07 2009]
a(n) = 5-2*cos(Pi*n/6) -2*sin(Pi*n/6)/3 -10*sin(Pi*n/2)/3 -2*cos(5*Pi*n/6) -2*sin(5*Pi*n/6)/3. - R. J. Mathar, Oct 08 2011
MATHEMATICA
PadRight[{}, 120, {1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9}] (* Harvey P. Dale, May 02 2012 *)
CROSSREFS
Cf. A131711.
Sequence in context: A353049 A288093 A131608 * A348722 A349614 A349613
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Sep 14 2007
EXTENSIONS
More terms from Tracy Poff (tracy.poff(AT)gmail.com), Dec 21 2008
Even more periods from R. J. Mathar, Feb 07 2009
STATUS
approved