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 A086090 #7 Jun 06 2017 15:00:13
%S A086090 1,5,22,89,340,1247,4438,15437,52744,177659,591514,1950665,6381388,
%T A086090 20734391,66977950,215266373,688813072,2195513843,6973830946,
%U A086090 22083492161,69736736596,219669514415,690387505702,2165301501629
%N A086090 2^n+n3^n.
%C A086090 Binomial transform of A048474
%H A086090 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (8,-21,18).
%F A086090 G.f.: (1-3x+3x^2)/((1-2x)(1-3x)^2)
%t A086090 Table[2^n+n*3^n,{n,0,30}] (* or *) LinearRecurrence[{8,-21,18},{1,5,22},30] (* _Harvey P. Dale_, Jun 06 2017 *)
%Y A086090 Cf. A086091.
%K A086090 easy,nonn
%O A086090 0,2
%A A086090 _Paul Barry_, Jul 09 2003