This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A158068 Period length 6: repeat 1, 2, 2, 1, 5, 5. 3
 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2, 1, 5, 5, 1, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The sequence can be generated starting an array T(n,k) by placing the periodic sequence 1,2,5 (repeat 1,2,5) in the top row n=0, then defining the next rows by T(n+1,k) = T(n,k)*T(n,k+1) mod 9, which all have a period T(n,k)=T(n,k+3). One finds the periodicity T(n+6,k)=T(n,k), and then defines a(n)=T(n,1). Also the partial fraction expansion of (85+sqrt(12469))/138. Also the decimal expansion of 11105/90909. LINKS Index to sequences with linear recurrences with constant coefficients, signature (1,-1,1,-1,1). FORMULA a(n)= a(n-1) -a(n-2) +a(n-3) -a(n-4) +a(n-5). G.f.: (1+x+5*x^4+x^2)/((1-x)*(1-x+x^2)*(1+x+x^2)) [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 26 2009] EXAMPLE a(n)=(1/90)*{76*(n mod 6)+16*[(n+1) mod 6]-44*[(n+2) mod 6]+31*[(n+3) mod 6]+16*[(n+4) mod 6]+[(n+5) mod 6]}, with n>=0 [From Paolo P. Lava, Mar 17 2009] CROSSREFS Cf. A157742, A158012. Sequence in context: A099605 A079218 A079220 * A210879 A176265 A187307 Adjacent sequences:  A158065 A158066 A158067 * A158069 A158070 A158071 KEYWORD nonn,easy AUTHOR Paul Curtz, Mar 12 2009 EXTENSIONS Offset set to 0 - R. J. Mathar, Sep 17 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .