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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A174737 a(n) = a(n-1) - a(n-2), with a(0)=2, a(1)=-1. 2
2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2, 1, 3, 2, -1, -3, -2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

Rosen, Discrete Mathematics and its Applications, McGraw-Hill, 2007, p. 456, Question 1b.

LINKS

Table of n, a(n) for n=0..75.

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

FORMULA

From Paolo P. Lava, Aug 25 2010: (Start)

a(n) = ((1/2)-(1/2)*i*sqrt(3))^n + ((1/2)+(1/2)*i*sqrt(3))^n + ((2/3)*i)*sqrt(3)*(((1/2)+(1/2)*i*sqrt(3))^n - ((1/2)-(1/2)*i*sqrt(3))^n), with n >= 0.

a(n) = (1/6)*((n mod 6) - 2*((n+1) mod 6) - 3*((n+2) mod 6) - ((n+3) mod 6) + 2*((n+4) mod 6) + 3*((n+5) mod 6)), with n >= 0. (End)

G.f.: ( 2-3*x ) / ( 1-x+x^2 ). - R. J. Mathar, Jan 08 2011

MAPLE

a[0] := 2: a[1] := -1: for n from 2 to 80 do a[n] := a[n-1]-a[n-2] end do: seq(a[n], n = 0 .. 75); # Emeric Deutsch, Apr 05 2010

CROSSREFS

Sequence in context: A107338 A118123 A181743 * A131756 A212620 A194859

Adjacent sequences:  A174734 A174735 A174736 * A174738 A174739 A174740

KEYWORD

easy,sign

AUTHOR

Zachary Berger (zsb1244(AT)rit.edu), Mar 28 2010

EXTENSIONS

Typo in definition fixed by Emeric Deutsch, Apr 05 2010

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 21 03:06 EST 2019. Contains 320364 sequences. (Running on oeis4.)