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 A288835 #25 Apr 04 2020 20:35:13
%S A288835 6,45,243,1134,4860,19683,76545,288684,1062882,3838185,13640319,
%T A288835 47829690,165809592,569173311,1937102445,6543101592,21953827710,
%U A288835 73222472421,242912646603,801960412230,2636009007156,8629791392475,28148810469273,91507169819844
%N A288835 a(n) = (1/2!)*3^n*(n+3)*(n).
%H A288835 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9, -27, 27).
%F A288835 O.g.f.: z*3^1*(2-3*z)/(1-3*z)^3.
%F A288835 a(n) = A287768(n+3,4).
%t A288835 Table[(1/2!)*3^n*(n + 3) n, {n, 24}] (* _Michael De Vlieger_, Jun 23 2017 *)
%t A288835 LinearRecurrence[{9,-27,27},{6,45,243},30] (* _Harvey P. Dale_, Apr 04 2020 *)
%Y A288835 Column k=4 of A287768.
%Y A288835 Cf. A288834, A288836, A288838.
%K A288835 nonn
%O A288835 1,1
%A A288835 _Gregory Gerard Wojnar_, Jun 17 2017