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%I #37 Feb 27 2024 03:02:13
%S 1,2,8,20,68,188,596,1724,5300,15644,47444,141308,425972,1273820,
%T 3829652,11472572,34450484,103285916,309988820,929704316,2789637236,
%U 8367863132,25105686548,75312865340,225946984628,677824176668
%N a(n) = a(n-1) + 6*a(n-2) for n >= 2, a(0)=1, a(1)=2.
%H Harvey P. Dale, <a href="/A133467/b133467.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 (1,6).
%F G.f.: (1+x)/((1+2*x)*(1-3*x)).
%F a(n) = Sum_{k=0..n+1} A122950(n+1,k)*5^(n+1-k). - _Philippe Deléham_, Jan 08 2008
%p Digits := 50:
%p for n from 0 to 40 do round(.8*3^n+.2*(-2)^n) end do;
%p # _Matt C. Anderson_, Jul 18 2017
%t LinearRecurrence[{1,6},{1,2},30] (* _Harvey P. Dale_, Apr 05 2014 *)
%o (Sage) from sage.combinat.sloane_functions import recur_gen2b; it = recur_gen2b(1,2,1,6, lambda n: 0); [next(it) for i in range(0,29)] # _Zerinvary Lajos_, Jul 03 2008
%K easy,nonn
%O 0,2
%A _Philippe Deléham_, Jan 03 2008
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