This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A083330 #10 Jul 02 2023 18:05:22
%S A083330 1,4,17,73,311,1309,5447,22453,91871,373789,1514327,6115333,24636431,
%T A083330 99073069,397878407,1596280213,6399436991,25640729149,102691925687,
%U A083330 411154861093,1645781181551,6586610462029,26356900104167
%N A083330 a(n) = (3*4^n - 2*3^n + 2^n)/2.
%C A083330 Binomial transform of A053156.
%H A083330 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9, -26, 24).
%F A083330 a(n) = (3*4^n - 2*3^n + 2^n)/2.
%F A083330 G.f.: (1-5x+7x^2)/(2(1-2x)(1-3x)(1-4x)).
%F A083330 E.g.f.: (3*exp(4x) - 2*exp(3x) + exp(2x))/2.
%t A083330 Table[(3 4^n-2 3^n+2^n)/2,{n,0,30}] (* _Harvey P. Dale_, Mar 14 2011 *)
%Y A083330 Cf. A083331.
%K A083330 easy,nonn
%O A083330 0,2
%A A083330 _Paul Barry_, Apr 27 2003