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A173262
a(n) = (2*10^n+61)/9
0
9, 29, 229, 2229, 22229, 222229, 2222229, 22222229, 222222229, 2222222229, 22222222229, 222222222229, 2222222222229, 22222222222229, 222222222222229, 2222222222222229, 22222222222222229, 222222222222222229
OFFSET
1,1
COMMENTS
n-1 2's followed by a 9.
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
Sequence in context: A146413 A146054 A321588 * A337445 A291159 A104516
KEYWORD
easy,nonn
AUTHOR
Ivan Panchenko, Feb 14 2010
EXTENSIONS
Extended by R. J. Mathar, Feb 21 2010
STATUS
approved