OFFSET
1,1
COMMENTS
n-1 2's followed by a 9.
LINKS
Markus Tervooren, Factorizations of (2)w9
Index entries for linear recurrences with constant coefficients, signature (11, -10).
FORMULA
a(n)= 11*a(n-1) -10*a(n-2). G.f.: x*(-9+70*x)/((10*x-1)*(1-x)). [From R. J. Mathar, Feb 21 2010]
a(n)=10*a(n-1)-61, (with a(1)=9) [From Vincenzo Librandi, Feb 24 2010]
MATHEMATICA
Table[10FromDigits[PadRight[{}, n, 2]]+9, {n, 0, 20}] (* or *) LinearRecurrence[ {11, -10}, {9, 29}, 20] (* Harvey P. Dale, Apr 09 2019 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Ivan Panchenko, Feb 14 2010
EXTENSIONS
Extended by R. J. Mathar, Feb 21 2010
STATUS
approved