%I #12 Sep 08 2022 08:45:49
%S 3,18,108,648,3888,23328,139968,839808,5038848,30233088,181398528,
%T 1088391168,6530347008,39182082048,235092492288,1410554953728,
%U 8463329722368,50779978334208,304679870005248,1828079220031488
%N a(n) = 3*6^n.
%C a(n) = A081341(n+1).
%C Essentially first differences of A125682.
%C Binomial transform of A005053 without initial term 1.
%C Second binomial transform of A164346.
%C Inverse binomial transform of A169634.
%C Second inverse binomial transform of A103333 without initial term 1.
%C Contribution from _Reinhard Zumkeller_, May 02 2010: (Start)
%C a(n) = 3*A000400(n) = A000400(n+1)/2;
%C subsequence of A003586; a(n)=A003586(A014105(n)) for n<6. (End)
%H Vincenzo Librandi, <a href="/A169604/b169604.txt">Table of n, a(n) for n = 0..300</a>
%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (6).
%F a(n) = 6*a(n-1) for n > 0; a(0) = 3.
%F G.f.: 3/(1-6*x).
%o (Magma) [ 3*6^n: n in [0..19] ];
%o (PARI) a(n)=3*6^n \\ _Charles R Greathouse IV_, Oct 16 2015
%Y Cf. A081341, A125682 ((6^n-1)*3/5), A005053 (expand (1-2x)/(1-5x)), A164346 (3*4^n), A169634 (3*7^n), A103333 (expand (1-5x)/(1-8x)).
%K nonn,easy
%O 0,1
%A _Klaus Brockhaus_, Apr 04 2010