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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A171507 a(n) = (5*2^(n+1)-9-(-1)^n)/6-2*n. 2
0, 0, 1, 6, 17, 42, 93, 198, 409, 834, 1685, 3390, 6801, 13626, 27277, 54582, 109193, 218418, 436869, 873774, 1747585, 3495210, 6990461, 13980966, 27961977, 55924002, 111848053, 223696158, 447392369, 894784794, 1789569645, 3579139350, 7158278761, 14316557586 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (3, -1, -3, 2).

FORMULA

a(n) = 3*a(n-1)-a(n-2)-3*a(n-3)+2*a(n-4). G.f.: x^2*(1+3*x)/((1+x)*(1-2*x)*(1-x)^2).

a(n) = A084640(n) - A042948(n).

a(n+1)-2*a(n) = A042948(n+1).

First differences: a(n+1)-a(n) = A084640(n).

Last digits: a(n) == a(n+10) (mod 10), n>=1.

MAPLE

A171507:=n->(5*2^(n+1)-9-(-1)^n)/6 -2*n: seq(A171507(n), n=0..50); # Wesley Ivan Hurt, May 03 2017

PROG

(MAGMA) [(5*2^(n+1)-9-(-1)^n)/6 -2*n: n in [0..40]]; // Vincenzo Librandi, Aug 05 2011

CROSSREFS

Cf. A042948, A084640.

Sequence in context: A013319 A047861 A343518 * A099858 A232567 A062020

Adjacent sequences:  A171504 A171505 A171506 * A171508 A171509 A171510

KEYWORD

nonn,easy

AUTHOR

Paul Curtz, Dec 10 2009

EXTENSIONS

Edited and extended by R. J. Mathar, Dec 15 2009

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 December 1 16:23 EST 2021. Contains 349430 sequences. (Running on oeis4.)