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!)
A130784 Period 3: repeat [1, 3, 2]. 9
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, 1, 3, 2, 1, 3, 2, 1, 3, 2, 1, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Continued fraction expansion of (3+sqrt(37))/7 (A176977). [Klaus Brockhaus, Apr 30 2010]

Pairwise sums of A010872(n). - Wesley Ivan Hurt, Jul 08 2014

Decimal expansion of 44/333. - David A. Corneth, Jul 02 2016

LINKS

Table of n, a(n) for n=0..85.

Index entries for linear recurrences with constant coefficients, signature (0,0,1).

FORMULA

a(n) = (n mod 3) + ((n+1) mod 3). - Paolo P. Lava, Jul 18 2007

a(n) = 4 - n + 3 * floor((n-1)/3). - Wesley Ivan Hurt, Nov 30 2013

a(n) = A080425(n) + 1. - Wesley Ivan Hurt, Jul 08 2014

a(n) = 3 - (n+5 mod 3) = 1 + (-n mod 3). - Wesley Ivan Hurt, Aug 29 2014

a(n) = 3*a(n-1)^2/2 - 13*a(n-1)/2 + 8. - Robert Israel, Aug 29 2014

O.g.f.: (1+z)*(1+2*z)/(1-z^3). - Robert Israel, Aug 29 2014

E.g.f.: 2*exp(z) - 2/sqrt(3)*exp(-z/2)*cos(sqrt(3)*z/2+Pi/6). - Robert Israel, Aug 29 2014

a(n) = a(n-3) for n>2. - Wesley Ivan Hurt, Jul 02 2016

MAPLE

A130784:=n->4-n+3*floor((n-1)/3); seq(A130784(n), n=0..100); # Wesley Ivan Hurt, Nov 30 2013

MATHEMATICA

PadRight[{}, 111, {1, 3, 2}] (* Harvey P. Dale, Apr 20 2012 *)

CoefficientList[Series[(1 + 3 x + 2 x^2)/(1 - x^3), {x, 0, 120}], x] (* Michael De Vlieger, Jul 02 2016 *)

PROG

(PARI) a(n)=[1, 3, 2][n%3+1] \\ Charles R Greathouse IV, Jun 02 2011

(MAGMA) [(n mod 3) + ((n+1) mod 3) : n in [0..100]]; // Wesley Ivan Hurt, Jul 08 2014

CROSSREFS

Cf. A010872, A080425, A176977.

Sequence in context: A236966 A280048 A119910 * A138034 A229216 A087818

Adjacent sequences:  A130781 A130782 A130783 * A130785 A130786 A130787

KEYWORD

nonn,easy

AUTHOR

Paul Curtz, Jul 15 2007

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 19 16:10 EST 2017. Contains 294936 sequences.