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

 

Logo

"Email this user" was broken Aug 14 to 9am Aug 16. If you sent someone a message in this period, please send it again.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A013726 21^(2n+1). 3
21, 9261, 4084101, 1801088541, 794280046581, 350277500542221, 154472377739119461, 68122318582951682301, 30041942495081691894741, 13248496640331026125580781, 5842587018385982521381124421 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (441).

FORMULA

a(n)=441*a(n-1), n>0 ; a(0)=21 . G.f.: 21/(1-441*x). - Philippe Deléham, Nov 28 2008

a(n) = A009965(A005408(n)). - Wesley Ivan Hurt, Feb 10 2014

MAPLE

seq(21^(2*n+1), n=0..10); # Nathaniel Johnston, Jun 25 2011

MATHEMATICA

Table[21^(2 n + 1), {n, 0, 15}] (* Wesley Ivan Hurt, Feb 10 2014 *)

PROG

(MAGMA) [21^(2*n+1): n in [0..15]]; // Vincenzo Librandi, Jun 26 2011

(PARI) a(n)=21^(2*n+1) \\ Charles R Greathouse IV, Jul 11 2016

CROSSREFS

Cf. A013708-A013725, A013727-A013729.

Sequence in context: A263278 A176446 A135823 * A159358 A048914 A046183

Adjacent sequences:  A013723 A013724 A013725 * A013727 A013728 A013729

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

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 August 21 09:54 EDT 2017. Contains 290864 sequences.