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A091928 a(0)=1, a(1)=5; a(n) = 6*a(n-1) + 5*a(n-2) for n > 1. 4
1, 5, 35, 235, 1585, 10685, 72035, 485635, 3273985, 22072085, 148802435, 1003175035, 6763062385, 45594249485, 307380808835, 2072256100435, 13970440646785, 94183924382885, 634955749531235, 4280654119101835 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Let the generator matrix for the ternary Golay G_12 code be [I|B], where the elements of B are taken from the set {0,1,2}. Then a(n)=sum of first row of B^n.

LINKS

Table of n, a(n) for n=0..19.

Index entries for linear recurrences with constant coefficients, signature (6,5).

FORMULA

G.f.: (1-x)/(1-6x-5x^2).

a(n) = (3+sqrt(14))^n(1/sqrt(14)+1/2) + (3-sqrt(14))^n(1/2-1/sqrt(14)).

a(n) = Sum_{k=0..n} 5^k*A122542(n,k). Lim_{n->infinity} a(n+1)/a(n) = 3 + sqrt(14) = 6.741657386773.... - Philippe Deléham, Sep 22 2006

CROSSREFS

Cf. A015551.

Sequence in context: A166176 A154780 A007995 * A305739 A290903 A155127

Adjacent sequences:  A091925 A091926 A091927 * A091929 A091930 A091931

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Feb 13 2004

EXTENSIONS

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Jun 05 2007

STATUS

approved

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Last modified February 19 10:03 EST 2020. Contains 332041 sequences. (Running on oeis4.)