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 A288838 #16 May 15 2022 18:29:26
%S A288838 54,729,6075,40095,229635,1194102,5786802,26572050,116917020,
%T A288838 496897335,2051893701,8269753401,32643763425,126557359740,
%U A288838 482984209620,1817776934388,6757388169138,24843338857125,90429753439935,326206114635555,1167092987918319,4144371018322194
%N A288838 a(n) = (1/4!)*3^(n+2)*(n+7)*(n+2)*(n+1)*(n).
%H A288838 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (15,-90,270,-405,243).
%F A288838 O.g.f.: z*3^3*(2-3*z)/(1-3*z)^5.
%F A288838 a(n) = A287768(n+7,9).
%t A288838 Table[1/4! 3^(n+2) (n+7)(n+2)(n+1)n,{n,30}] (* or *) LinearRecurrence[{15,-90,270,-405,243},{54,729,6075,40095,229635},30] (* _Harvey P. Dale_, May 15 2022 *)
%o A288838 (PARI) a(n)=3^n*3*n*(n+1)*(n+2)*(n+7)/8 \\ _Charles R Greathouse IV_, Jun 19 2017
%Y A288838 Column k=9 of A287768.
%Y A288838 Cf. A288834, A288835, A288836.
%K A288838 nonn,easy
%O A288838 1,1
%A A288838 _Gregory Gerard Wojnar_, Jun 17 2017