A173813 - OEIS

A173813

2*(10^n-5), n>0.

10, 190, 1990, 19990, 199990, 1999990, 19999990, 199999990, 1999999990, 19999999990, 199999999990, 1999999999990, 19999999999990, 199999999999990, 1999999999999990, 19999999999999990, 199999999999999990

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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 *)

LinearRecurrence[{11, -10}, {10, 190}, 20] (* Harvey P. Dale, Aug 20 2023 *)

PROG

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

CROSSREFS

Sequence in context: A365175 A239765 A006409 * A249643 A056174 A033714

Adjacent sequences: A173810 A173811 A173812 * A173814 A173815 A173816

KEYWORD

nonn

AUTHOR

Vincenzo Librandi

STATUS

approved