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a(n) = ((5+sqrt(5))*(4+sqrt(5))^n + (5-sqrt(5))*(4-sqrt(5))^n)/10.
4

%I #13 Oct 25 2023 12:19:19

%S 1,5,29,177,1097,6829,42565,265401,1654993,10320533,64359341,

%T 401348865,2502838169,15607867837,97331722837,606967236489,

%U 3785088940705,23604071924261,147196597046333,917927985203793,5724261314120681,35696882675723725,222608186950462309,1388199786170737497

%N a(n) = ((5+sqrt(5))*(4+sqrt(5))^n + (5-sqrt(5))*(4-sqrt(5))^n)/10.

%C Binomial transform of A082761. Fourth binomial transform of A074872.

%H G. C. Greubel, <a href="/A163073/b163073.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,-11).

%F a(n) = 8*a(n-1)-11*a(n-2) for n > 1; a(0) = 1, a(1) = 5.

%F G.f.: (1-3*x)/(1-8*x+11*x^2).

%F E.g.f.: exp(4*x)*(5*cosh(sqrt(5)*x) + sqrt(5)*sinh(sqrt(5)*x))/5. - _Stefano Spezia_, Oct 25 2023

%t LinearRecurrence[{8,-11},{1,5},30] (* _Harvey P. Dale_, Dec 11 2017 *)

%o (Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-5); S:=[ ((5+r)*(4+r)^n+(5-r)*(4-r)^n)/10: n in [0..20] ]; [ Integers()!S[j]: j in [1..#S] ]; // _Klaus Brockhaus_, Jul 24 2009

%o (PARI) x='x+O('x^30); Vec((1-3*x)/(1-8*x+11*x^2)) \\ _G. C. Greubel_, Jan 08 2018

%Y Cf. A082761, A074872 (1,1,5,5,25,25,...).

%K nonn,easy

%O 0,2

%A Al Hakanson (hawkuu(AT)gmail.com), Jul 20 2009

%E Edited and extended beyond a(5) by _Klaus Brockhaus_, Jul 24 2009