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%I #18 Apr 25 2023 13:29:36
%S 0,5,65,665,6305,58025,527345,4766585,42981185,387158345,3485735825,
%T 31376865305,282412759265,2541798719465,22876524019505,
%U 205890058352825,1853015893884545,16677164519797385,150094566577522385
%N a(n) = 9^n - 4^n.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CantorSquareFractal.html">Cantor Square Fractal</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (13,-36)
%F a(n) = 5*A016153(n).
%F a(n) = 13*a(n-1) - 36*a(n-2), n>=2. - _Vincenzo Librandi_, Mar 16 2011
%F G.f.: 5*x / ( (9*x-1)*(4*x-1) ). - _R. J. Mathar_, Mar 18 2011
%t Table[9^n-4^n,{n,0,20}] (* or *) LinearRecurrence[{13,-36},{0,5},20] (* _Harvey P. Dale_, May 11 2017 *)
%o (PARI) a(n)=9^n-4^n \\ _Charles R Greathouse IV_, Oct 07 2015
%Y Cf. A016153.
%K nonn,easy
%O 0,2
%A _Eric W. Weisstein_, Apr 09 2006
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