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A173834
a(n)=10^n-2*n
1
1, 8, 96, 994, 9992, 99990, 999988, 9999986, 99999984, 999999982, 9999999980, 99999999978, 999999999976, 9999999999974, 99999999999972, 999999999999970, 9999999999999968, 99999999999999966, 999999999999999964
OFFSET
0,2
FORMULA
G.f.: (1-4*x+21*x^2)/((1-x)^2*(1-10*x)). - Vincenzo Librandi, Jul 15 2012
a(n) = 10*a(n-1) +18*n -38 = 12*a(n-1) -21*a(n-2) +10*a(n-3). - Vincenzo Librandi, Jul 15 2012
MATHEMATICA
CoefficientList[Series[(1-4*x+21*x^2)/((1-x)^2*(1-10*x)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 15 2012 *)
PROG
(Magma) [10^n-2*n: n in [0..20]]; // Vincenzo Librandi, Jul 15 2012
CROSSREFS
Sequence in context: A099675 A211345 A060458 * A260627 A098430 A365847
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Feb 26 2010
STATUS
approved