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 A086653 #18 Mar 08 2025 15:34:55
%S A086653 5,10,17,28,47,82,149,280,539,1054,2081,4132,8231,16426,32813,65584,
%T A086653 131123,262198,524345,1048636,2097215,4194370,8388677,16777288,
%U A086653 33554507,67108942,134217809,268435540,536870999,1073741914,2147483741
%N A086653 a(n) = 2^n + 3*n.
%H A086653 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2).
%F A086653 From _Colin Barker_, Sep 05 2012: (Start)
%F A086653 a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3).
%F A086653 G.f.: x*(5-10*x+2*x^2)/((1-x)^2*(1-2*x)). (End)
%F A086653 a(n) = A000079(n) + A008585(n). - _Michel Marcus_, Mar 23 2024
%F A086653 E.g.f.: exp(x)*(exp(x) + 3*x) - 1. - _Elmo R. Oliveira_, Mar 08 2025
%p A086653 seq(2^n + 3*n,n=1..40);
%t A086653 Table[2^n+3n,{n,40}] (* or *) LinearRecurrence[{4,-5,2},{5,10,17},40] (* _Harvey P. Dale_, Dec 12 2013 *)
%Y A086653 Cf. A000079, A008585.
%K A086653 easy,nonn
%O A086653 1,1
%A A086653 Robert H Rosseau (rhrosseau(AT)yahoo.com), Sep 11 2003
%E A086653 More terms from _Ray Chandler_, Sep 16 2003