A131029 Periodic sequence (11, 5, 2, 5, 11, 14).

11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14, 11, 5, 2, 5, 11, 14

Offset

1,1

Comments

Fifth column of triangular array T defined in A131022.

Links

Table of n, a(n) for n=1..84.

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

Formula

a(1) = a(5) = 11, a(2) = a(4) = 5, a(3) = 2, a(6) = 14; for n > 6, a(n) = a(n-6).

G.f.: (11-17*x+14*x^2)/((1-x)*(1-x+x^2)).

a(n) = 3*cos((n-1)/3*Pi)-3*sqrt(3)*sin((n-1)/3*Pi)+8. - Leonid Bedratyuk, May 13 2012

Mathematica

PadRight[{}, 120, {11, 5, 2, 5, 11, 14}] (* or *) LinearRecurrence[{2, -2, 1}, {11, 5, 2}, 120] (* Harvey P. Dale, Jun 12 2017 *)

Prog

(PARI) {m=84; for(n=1, m, r=(n-1)%6; print1(if(r==0||r==4, 11, if(r==2, 2, if(r==5, 14, 5))), ", "))}
(Magma) m:=84; [ [11, 5, 2, 5, 11, 14][(n-1) mod 6 + 1]: n in [1..m] ];
(Python)
def a(n): return [11, 5, 2, 5, 11, 14][n%6]
print([a(n) for n in range(84)]) # Michael S. Branicky, Nov 05 2021

Crossrefs

Cf. A131022. Other columns of T are in A088911, A131026, A131027, A131028, A131030.

Sequence in context: A038318 A010186 A097531 * A033331 A229192 A303978

Adjacent sequences: A131026 A131027 A131028 * A131030 A131031 A131032

Keyword

nonn,easy

Author

Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 10 2007

Status

approved