OFFSET
0,2
LINKS
FORMULA
a(n) = (9^n - 1)*5/8.
a(n) = 9*a(n-1) + 5 with n > 0, a(0)=0. - Vincenzo Librandi, Sep 30 2010
From Chai Wah Wu, Mar 12 2018: (Start)
a(n) = 10*a(n-1) - 9*a(n-2) for n > 1.
G.f.: 5*x/((1 - x)*(1 - 9*x)). (End)
MATHEMATICA
FromDigits[#, 9]&/@ Table[PadRight[{5}, n, 5], {n, 0, 20}] (* Harvey P. Dale, Jan 27 2011 *)
PROG
(PARI) a(n) = (9^n-1)*5/8; \\ Altug Alkan, Mar 12 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zerinvary Lajos, Feb 03 2007
STATUS
approved