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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A163495 a(0)=0, a(1)=1, a(2)=2. For n >= 3, a(n) = a(n-1) - min(a(n-2), a(n-3)). 1
0, 1, 2, 2, 1, -1, -2, -1, 1, 3, 4, 3, 0, -3, -3, 0, 3, 6, 6, 3, -3, -6, -3, 3, 9, 12, 9, 0, -9, -9, 0, 9, 18, 18, 9, -9, -18, -9, 9, 27, 36, 27, 0, -27, -27, 0, 27, 54, 54, 27, -27, -54, -27, 27, 81, 108, 81, 0, -81, -81, 0, 81, 162, 162, 81, -81, -162, -81, 81, 243, 324, 243, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n+15) = 3*a(n) for all n. - Dion Gijswijt (gijswijt(AT)science.uva.nl) Jul 29 2009 on SeqFan mailing list.

LINKS

A. Karttunen, Table of n, a(n) for n=0..224

FORMULA

G.f. x*(1 +2*x +2*x^2 +x^3 -x^4 -2*x^5 -x^6 +x^7 +3*x^8 +4*x^9 +3*x^10 -3*x^12 -3*x^13) / (1 - 3*x^15 ). - R. J. Mathar, Jun 22 2011

MAPLE

a[0] := 0: a[1] := 1: a[2] := 2: for n from 3 to 80 do a[n] := a[n-1]-min(a[n-2], a[n-3]) end do: seq(a[n], n = 0 .. 80); # Emeric Deutsch, Aug 01 2009

MATHEMATICA

CoefficientList[Series[x*(1 +2*x +2*x^2 +x^3 -x^4 -2*x^5 -x^6 +x^7 +3*x^8 +4*x^9 +3*x^10 -3*x^12 -3*x^13)/(1 - 3*x^15 ), {x, 0, 50}], x] (* G. C. Greubel, Jul 26 2017 *)

PROG

(PARI) x='x+O('x^50); concat([0], Vec(x*(1 +2*x +2*x^2 +x^3 -x^4 -2*x^5 -x^6 +x^7 +3*x^8 +4*x^9 +3*x^10 -3*x^12 -3*x^13)/(1 - 3*x^15 ))) \\ G. C. Greubel, Jul 26 2017

CROSSREFS

Sequence in context: A202205 A075661 A206829 * A060709 A035222 A136436

Adjacent sequences:  A163492 A163493 A163494 * A163496 A163497 A163498

KEYWORD

sign

AUTHOR

Leroy Quet, Jul 29 2009

EXTENSIONS

Extended by Emeric Deutsch, Aug 01 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 21 22:32 EST 2017. Contains 295054 sequences.