A177080 - OEIS

A177080

a(n) = 5*(10^n-7).

15, 465, 4965, 49965, 499965, 4999965, 49999965, 499999965, 4999999965, 49999999965, 499999999965, 4999999999965, 49999999999965, 499999999999965, 4999999999999965, 49999999999999965, 499999999999999965

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OFFSET

1,1

LINKS

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

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

FORMULA

G.f.: 15*x*(1+20*x) / ( (10*x-1)*(x-1) ). a(n) = 15*A033175(n-1). - R. J. Mathar, Jan 05 2011

CROSSREFS

Sequence in context: A209488 A361307 A320097 * A306609 A272905 A005815

Adjacent sequences: A177077 A177078 A177079 * A177081 A177082 A177083

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi

STATUS

approved