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A177109 a(n) = 4*(10^n-5). 1
20, 380, 3980, 39980, 399980, 3999980, 39999980, 399999980, 3999999980, 39999999980, 399999999980, 3999999999980, 39999999999980, 399999999999980, 3999999999999980, 39999999999999980, 399999999999999980 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Is this 20*A067272(n)?

LINKS

Table of n, a(n) for n=1..17.

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

FORMULA

G.f.: 20*x*(1+8*x) / ( (10*x-1)*(x-1) ). - R. J. Mathar, Jan 06 2011

MAPLE

A177109:=n->4*(10^n-5): seq(A177109(n), n=1..30); # Wesley Ivan Hurt, Feb 16 2017

CROSSREFS

Cf. A067272.

Sequence in context: A178352 A266736 A019580 * A162806 A084329 A097832

Adjacent sequences:  A177106 A177107 A177108 * A177110 A177111 A177112

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Nov 15 2010

STATUS

approved

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Last modified July 16 23:49 EDT 2019. Contains 325092 sequences. (Running on oeis4.)