A131707 Period 12: repeat 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, 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]

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) = 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

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