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!)
A087288 a(n)=2a(n-1)+a(n-2)-2a(n-3). 5
4, 4, 10, 16, 34, 64, 130, 256, 514, 1024, 2050, 4096, 8194, 16384, 32770, 65536, 131074, 262144, 524290, 1048576, 2097154, 4194304, 8388610, 16777216, 33554434, 67108864, 134217730, 268435456, 536870914, 1073741824, 2147483650 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(n)=(A000051(n)-A014551(n))/2.

LINKS

Indranil Ghosh, Table of n, a(n) for n = 0..3314

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

FORMULA

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

MATHEMATICA

CoefficientList[Series[(4 - 4x - 2x^2)/(1 - 2x - x^2 + 2x^3), {x, 0, 30}], x]

PROG

(PARI) a(n)=2<<n+1+(-1)^n \\ Charles R Greathouse IV, Aug 20 2013

CROSSREFS

Sequence in context: A185904 A201618 A050339 * A185779 A095009 A178820

Adjacent sequences:  A087285 A087286 A087287 * A087289 A087290 A087291

KEYWORD

nonn,easy

AUTHOR

Mario Catalani (mario.catalani(AT)unito.it), Aug 31 2003

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 January 24 04:35 EST 2020. Contains 331183 sequences. (Running on oeis4.)