login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A191640 a(n) = floor((-1 + 4^n)/(-1 + 4*n)). 2
1, 2, 5, 17, 53, 178, 606, 2114, 7489, 26886, 97541, 356962, 1315860, 4880644, 18199013, 68174084, 256415957, 967879954, 3665038759, 13917868706, 52988512181, 202209034993, 773282903051, 2962894491691, 11372726331743, 43724268226898, 168358864574597 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

MATHEMATICA

f[n_] := Floor[(-1+4^n)/(-1+4 n)]

Table[f[n], {n, 1, 40}]     (* A191640 *)

PROG

(MAGMA) [Floor((-1+4^n)/(-1+4*n)): n in [1..30] ]; // Vincenzo Librandi, Sep 10 2011

(Maxima) A191640(n):=floor((-1+4^n)/(-1+4*n))$ makelist(A191640(n), n, 1, 30); /* Martin Ettl, Oct 25 2012 */

CROSSREFS

Cf. A191641.

Sequence in context: A141303 A263678 A133510 * A148408 A002692 A148409

Adjacent sequences:  A191637 A191638 A191639 * A191641 A191642 A191643

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jun 09 2011

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 24 04:36 EST 2020. Contains 332197 sequences. (Running on oeis4.)