|
Search: id:A158068
|
|
|
| A158068 |
|
Period length 6: repeat 1, 2, 2, 1, 5, 5. |
|
+0
4
|
|
| 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; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
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.
|
|
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 (ppl(AT)spl.at), Mar 17 2009]
|
|
CROSSREFS
|
Cf. A157742, A158012
Sequence in context: A099605 A079218 A079220 this_sequence A123971 A114292 A141751
Adjacent sequences: A158065 A158066 A158067 this_sequence A158069 A158070 A158071
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
Paul Curtz (bpcrtz(AT)free.fr), Mar 12 2009
|
|
EXTENSIONS
|
Offset set to 0 - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 17 2009
|
|
|
Search completed in 0.002 seconds
|
