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A131707 Period 12: repeat 1, 1, 3, 7, 7, 1, 9, 9, 7, 3, 3, 9 . 7
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Also the decimal expansion of 1023949/9000009. [From R. J. Mathar, Feb 07 2009]

LINKS

Table of n, a(n) for n=0..104.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,-1,1).

FORMULA

a(n)=(1/66)*{49*(n mod 12)-28*[(n+1) mod 12]+5*[(n+2) mod 12]+27*[(n+3) mod 12]+16*[(n+4) mod 12]+5*[(n+5) mod 12]-39*[(n+6) mod 12]+38*[(n+7) mod 12]+5*[(n+8) mod 12]-17*[(n+9) mod 12]-6*[(n+10) mod 12]+5*[(n+11) mod 12]}, with n>=0 - Paolo P. Lava, Oct 02 2007

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). [From 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: A227336 A288093 A131608 * A016620 A200691 A021269

Adjacent sequences:  A131704 A131705 A131706 * A131708 A131709 A131710

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

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Last modified November 13 11:09 EST 2018. Contains 317133 sequences. (Running on oeis4.)