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A166984 a(n) = 20*a(n-1) - 64*a(n-2) for n > 1; a(0) = 1, a(1) = 20. 6
1, 20, 336, 5440, 87296, 1397760, 22368256, 357908480, 5726601216, 91625881600, 1466015154176, 23456246661120, 375299963355136, 6004799480791040, 96076791961092096, 1537228672451215360, 24595658763514413056 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Partial sums of A166965.

lim_{n -> infinity} a(n)/a(n-1) = 16.

a(n) = A115490(n+1)/3.

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..830 (terms 0..200 from Vincenzo Librandi)

E. Saltürk and I. Siap, Generalized Gaussian Numbers Related to Linear Codes over Galois Rings, European Journal of Pure and Applied Mathematics, Vol. 5, No. 2, 2012, 250-259; ISSN 1307-5543. - From N. J. A. Sloane, Oct 23 2012

Index entries for linear recurrences with constant coefficients, signature (20, -64).

FORMULA

a(n) = (4*16^n - 4^n)/3.

G.f.: 1/((1-4*x)*(1-16*x)).

From Robert A. Russell, Apr 03 2013: (Start)

E.g.f.: sinh(x)^4/4!.

a(n) = Sum{n>=0, a(n) x^(2n+4)/(2n+4)!}. (End)

MATHEMATICA

LinearRecurrence[{20, -64}, {1, 20}, 30] (* Harvey P. Dale, Jul 04 2012 *)

PROG

(MAGMA) [ n le 2 select 19*n-18 else 20*Self(n-1)-64*Self(n-2): n in [1..17] ];

CROSSREFS

Cf. A006105, A166965, A115490, A166914, A166917, A166927, A002452, A002453, A307695.

Sequence in context: A187512 A144507 A084032 * A167031 A268787 A272183

Adjacent sequences:  A166981 A166982 A166983 * A166985 A166986 A166987

KEYWORD

nonn

AUTHOR

Klaus Brockhaus, Oct 26 2009

STATUS

approved

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Last modified September 15 08:37 EDT 2019. Contains 327062 sequences. (Running on oeis4.)