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A173813 2*(10^n-5),   n>0. 1
10, 190, 1990, 19990, 199990, 1999990, 19999990, 199999990, 1999999990, 19999999990, 199999999990, 1999999999990, 19999999999990, 199999999999990, 1999999999999990, 19999999999999990, 199999999999999990 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..100

Index entries for linear recurrences with constant coefficients, signature (11, -10).

FORMULA

G.f.: x*(10 + 80*x)/((1 - x)*(1 - 10*x)). - Vincenzo Librandi, Aug 20 2014

MATHEMATICA

Table[(2 (10^n - 5)), {n, 1, 20}] (* or *) CoefficientList[Series[(10 + 80 x)/((1 - x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Aug 20 2014 *)

PROG

(MAGMA) [2*(10^n-5): n in [1..20]]; // Vincenzo Librandi, Aug 20 2014

CROSSREFS

Sequence in context: A223146 A239765 A006409 * A249643 A056174 A033714

Adjacent sequences:  A173810 A173811 A173812 * A173814 A173815 A173816

KEYWORD

nonn

AUTHOR

Vincenzo Librandi

STATUS

approved

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Last modified January 28 09:17 EST 2020. Contains 331318 sequences. (Running on oeis4.)