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A155670
11^n+9^n-1^n
4
1, 19, 201, 2059, 21201, 220099, 2303001, 24270139, 257405601, 2745368179, 29424209001, 316692730219, 3420857913201, 37064577972259, 402626626038201, 4383139301510299, 47802750052424001, 522124210198960339
OFFSET
0,2
FORMULA
G.f.: 1/(1-11*x)+1/(1-9*x)-1/(1-x). E.g.f.: e^(11*x)+e^(9*x)-e^x.
a(n)=20*a(n-1)-99*a(n-2)-80 with a(0)=1, a(1)=19 - Vincenzo Librandi, Jul 21 2010
MATHEMATICA
Table[11^n+9^n-1^n, {n, 0, 30}] (* Harvey P. Dale, Mar 26 2011 *)
PROG
(PARI) a(n)=11^n+9^n-1^n \\ Charles R Greathouse IV, Oct 16 2015
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Feb 01 2009
STATUS
approved