OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..300
Index entries for linear recurrences with constant coefficients, signature (11,-10).
FORMULA
a(n) = 2*(10^n - 4).
R(a(n)) = A086947(n).
From Chai Wah Wu, Aug 01 2020: (Start)
a(n) = 11*a(n-1) - 10*a(n-2) for n > 2.
G.f.: x*(60*x + 12)/((x - 1)*(10*x - 1)). (End)
From Elmo R. Oliveira, May 01 2025: (Start)
E.g.f.: 2*(3 - 4*exp(x) + exp(10*x)).
MATHEMATICA
Table[10*FromDigits[PadRight[{1}, n, 9]]+2, {n, 20}] (* Harvey P. Dale, Dec 15 2017 *)
PROG
(Magma) [2*(10^n-4): n in [1..25] ]; // Vincenzo Librandi, Aug 22 2011
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Ray Chandler, Jul 24 2003
STATUS
approved