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%I #18 Sep 08 2022 08:45:10
%S 1,7,21,63,189,567,1701,5103,15309,45927,137781,413343,1240029,
%T 3720087,11160261,33480783,100442349,301327047,903981141,2711943423,
%U 8135830269,24407490807,73222472421,219667417263,659002251789,1977006755367
%N a(n) = (7*3^n - 4*0^n)/3.
%C Binomial transform of A083495.
%H Vincenzo Librandi, <a href="/A082541/b082541.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (3)
%F G.f.: (1+4*x)/(1-3*x).
%F E.g.f.: (7*exp(3*x) - 4*exp(0))/3.
%F a(n) = A005032(n-1), n > 0. - _R. J. Mathar_, Sep 17 2008
%t Join[{1},NestList[3#&,7,30]] (* _Harvey P. Dale_, May 07 2019 *)
%o (Magma) [(7*3^n-4*0^n)/3: n in [0..30]]; // _Vincenzo Librandi_, Sep 15 2011
%o (PARI) a(n)=(7*3^n-4*0^n)/3 \\ _Charles R Greathouse IV_, Oct 07 2015
%Y Cf. A083497.
%K nonn,easy
%O 0,2
%A _Paul Barry_, May 02 2003
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