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a(n) = ((5 + 2*sqrt(2))*(4 + sqrt(2))^n + (5 - 2*sqrt(2))*(4 - sqrt(2))^n)/2.
4

%I #13 Sep 08 2022 08:45:46

%S 5,24,122,640,3412,18336,98920,534656,2892368,15653760,84736928,

%T 458742784,2483625280,13446603264,72802072192,394164131840,

%U 2134084044032,11554374506496,62557819435520,338701312393216,1833801027048448

%N a(n) = ((5 + 2*sqrt(2))*(4 + sqrt(2))^n + (5 - 2*sqrt(2))*(4 - sqrt(2))^n)/2.

%C Binomial transform of A163609. Fourth binomial transform of A163888. Inverse binomial transform of A163611.

%H Harvey P. Dale, <a href="/A163610/b163610.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,-14).

%F a(n) = 8*a(n-1) - 14*a(n-2) for n > 1; a(0) = 5, a(1) = 24.

%F G.f.: (5-16*x)/(1-8*x+14*x^2).

%F E.g.f.: exp(4*x)*( 5*cosh(sqrt(2)*x) + 2*sqrt(2)*sinh(sqrt(2)*x) ). - _G. C. Greubel_, Jul 29 2017

%t LinearRecurrence[{8,-14},{5,24},30] (* _Harvey P. Dale_, May 29 2016 *)

%o (Magma) Z<x>:= PolynomialRing(Integers()); N<r>:=NumberField(x^2-2); S:=[ ((5+2*r)*(4+r)^n+(5-2*r)*(4-r)^n)/2: n in [0..20] ]; [ Integers()!S[j]: j in [1..#S] ]; // _Klaus Brockhaus_, Aug 06 2009

%o (PARI) x='x+O('x^50); Vec((5-16*x)/(1-8*x+14*x^2)) \\ _G. C. Greubel_, Jul 29 2017

%Y Cf. A163609, A163611, A163888.

%K nonn

%O 0,1

%A Al Hakanson (hawkuu(AT)gmail.com), Aug 01 2009

%E Edited and extended beyond a(5) by _Klaus Brockhaus_, Aug 06 2009