OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (110,-1000).
FORMULA
a(n) = floor((1000^n)/(10^n + 1)).
a(n) = 9*A138147(n), for n>0.
a(n) = A168624(n) - 1.
a(n) = Sum_{k=1..n} 9*10^(2n-k).
a(n) = ((10^n)*A002283(2n))/(10^n + 1).
From Chai Wah Wu, Sep 01 2016: (Start)
a(n) = 110*a(n-1) - 1000*a(n-2) for n > 1.
G.f.: 90*x/((10*x - 1)*(100*x - 1)). (End)
E.g.f.: exp(10*x)*(exp(90*x) - 1). - Elmo R. Oliveira, Aug 14 2024
MAPLE
MATHEMATICA
Table[100^n - 10^n, {n, 0, 10}] (* Alonso del Arte, Aug 31 2016 *)
PROG
(PARI) a(n)=100^n-10^n \\ Charles R Greathouse IV, Sep 01 2016
(Magma) [100^n-10^n : n in [0..20]]; // Wesley Ivan Hurt, Sep 07 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Carauleanu Marc, Aug 31 2016
STATUS
approved