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A131029
Periodic sequence (11, 5, 2, 5, 11, 14).
10
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.
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
KEYWORD
nonn,easy
AUTHOR
Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 10 2007
STATUS
approved