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%I #16 Apr 18 2024 09:32:27
%S 1,11,71,431,2591,15551,93311,559871,3359231,20155391,120932351,
%T 725594111,4353564671,26121388031,156728328191,940369969151,
%U 5642219814911,33853318889471,203119913336831,1218719480020991,7312316880125951,43873901280755711,263243407684534271
%N a(n) = 6^n/3 - 1.
%H Vincenzo Librandi, <a href="/A164559/b164559.txt">Table of n, a(n) for n = 1..600</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (7,-6).
%F a(n) = 6*a(n-1)+5 for n > 2; a(1) = 1, a(2) = 11.
%F G.f.: x*(1+4*x)/((1-x)*(1-6*x)).
%o (Magma) [ 6^n/3-1: n in [1..20] ];
%Y Cf. A000400 (powers of 6), A024062 (6^n-1), A164560.
%K nonn,easy,changed
%O 1,2
%A _Klaus Brockhaus_, Aug 16 2009
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