login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A116530 a(n) = 3*a(n-1), with a(1) = 20. 1
20, 60, 180, 540, 1620, 4860, 14580, 43740, 131220, 393660, 1180980, 3542940, 10628820, 31886460, 95659380, 286978140, 860934420, 2582803260, 7748409780, 23245229340, 69735688020, 209207064060, 627621192180, 1882863576540 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (3).

FORMULA

a(n) = 10*A008776(n+1).

G.f.: 20*x/(1-3*x). - Philippe Deléham, Nov 23 2008

From G. C. Greubel, Oct 31 2016: (Start)

a(n) = 20*3^(n-1).

E.g.f.: (20/3)*(exp(3*x) - 1). (End)

MATHEMATICA

Table[4*5*3^(n - 1), {n, 24}] (* Robert G. Wilson v, May 19 2006 *)

LinearRecurrence[{3}, {20}, 25] (* G. C. Greubel, Oct 31 2016 *)

PROG

(MAGMA) [20*3^(n-1): n in [1..30]]; // Vincenzo Librandi, Oct 31 2016

CROSSREFS

Sequence in context: A163761 A154072 A078184 * A219830 A041780 A041782

Adjacent sequences:  A116527 A116528 A116529 * A116531 A116532 A116533

KEYWORD

nonn,less,easy

AUTHOR

Ben Gregson (mahishimi(AT)hotmail.com), Mar 26 2006

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 21 22:32 EST 2017. Contains 295054 sequences.