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A083226 a(n) = (8*9^n + (-9)^n)/9. 3
1, 7, 81, 567, 6561, 45927, 531441, 3720087, 43046721, 301327047, 3486784401, 24407490807, 282429536481, 1977006755367, 22876792454961, 160137547184727, 1853020188851841, 12971141321962887, 150094635296999121 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = (8*9^n + (-9)^n)/9.
G.f.: (1+7*x)/((1+9*x)*(1-9*x)).
E.g.f.: (8*exp(9*x) + exp(-9*x))/9.
a(n) = 81*a(n-2); a(0)=1, a(1)=7. - Harvey P. Dale, May 24 2012
MATHEMATICA
Table[(8*9^n+(-9)^n)/9, {n, 0, 20}] (* or *) LinearRecurrence[{0, 81}, {1, 7}, 20] (* Harvey P. Dale, May 24 2012 *)
PROG
(Magma) [(8*9^n+(-9)^n)/9: n in [0..25]]; // Vincenzo Librandi, Jun 29 2011
(PARI) a(n)=(8*9^n+(-9)^n)/9 \\ Charles R Greathouse IV, Jun 29 2011
CROSSREFS
Sequence in context: A373441 A171768 A050861 * A088735 A364322 A339710
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 23 2003
STATUS
approved

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Last modified June 22 01:41 EDT 2024. Contains 373561 sequences. (Running on oeis4.)