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10^n - 8^n.
0

%I #15 Sep 08 2022 08:46:10

%S 0,2,36,488,5904,67232,737856,7902848,83222784,865782272,8926258176,

%T 91410065408,931280523264,9450244186112,95601953488896,

%U 964815627911168,9718525023289344,97748200186314752,981985601490518016,9855884811924144128

%N 10^n - 8^n.

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (18,-80).

%F G.f.: 2*x/((1-8*x)*(1-10*x)).

%F a(n) = 18*a(n-1) - 80*a(n-2).

%F a(n) = 2^n*(5^n-4^n) = A000079(n) * A005060(n) = A011557(n) - A001018(n).

%F a(n+1) = 2*A016186(n).

%t Table[10^n - 8^n, {n, 0, 25}] (* or *) CoefficientList[Series[2 x/((1 - 8 x) (1 - 10 x)), {x, 0, 30}], x]

%t LinearRecurrence[{18,-80},{0,2},30] (* _Harvey P. Dale_, May 21 2018 *)

%o (Magma) [10^n-8^n: n in [0..30]];

%Y Cf. A016185, A016186, A139746.

%K nonn,easy

%O 0,2

%A _Vincenzo Librandi_, Oct 05 2014