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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A156550 5*(-1)^n*A078008(n). 0
5, 0, 10, -10, 30, -50, 110, -210, 430, -850, 1710, -3410, 6830, -13650, 27310, -54610, 109230, -218450, 436910, -873810, 1747630, -3495250, 6990510, -13981010, 27962030, -55924050, 111848110, -223696210, 447392430, -894784850, 1789569710, -3579139410 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..31.

FORMULA

a(n) = A140966(n)+A140966(n+2).

a(n) = 3*A140966(n)-A140966(n+1). a(n+1)=10*(-1)^n*A001045(n).

G.f.: 5*(1+x)/(1+x-2*x^2). - R. J. Mathar, Feb 23 2009

a(n) = (5*(2+(-2)^n))/3. - Colin Barker, Jun 10 2012

CROSSREFS

Sequence in context: A275792 A010481 A291724 * A088307 A208477 A007392

Adjacent sequences:  A156547 A156548 A156549 * A156551 A156552 A156553

KEYWORD

sign,easy,less

AUTHOR

Paul Curtz, Feb 09 2009

EXTENSIONS

Edited and extended by R. J. Mathar Feb 23 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 November 13 07:13 EST 2019. Contains 329085 sequences. (Running on oeis4.)