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A175237
2*(10^n - 7).
1
6, 186, 1986, 19986, 199986, 1999986, 19999986, 199999986, 1999999986, 19999999986, 199999999986, 1999999999986, 19999999999986, 199999999999986, 1999999999999986, 19999999999999986, 199999999999999986
OFFSET
1,1
FORMULA
G.f.: 6*x*(1 + 20*x)/((1-x)*(1-10*x)). - Vincenzo Librandi, Apr 26 2014
MATHEMATICA
Join[{6}, Table[FromDigits[Join[{1}, PadLeft[{8, 6}, n, 9]]], {n, 2, 20}]] (* Harvey P. Dale, Mar 22 2012 *)
CoefficientList[Series[6 (1 + 20 x)/((1 - x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Apr 26 2014 *)
PROG
(Magma) [2*(10^n-7): n in [1..20]]; // Vincenzo Librandi, Apr 26 2014
CROSSREFS
Sequence in context: A012181 A012224 A274272 * A222335 A037298 A272467
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 15 2010
STATUS
approved