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 A074526 #19 Sep 08 2022 08:45:07
%S A074526 3,9,29,99,353,1299,4889,18699,72353,282339,1108649,4373499,17312753,
%T A074526 68711379,273234809,1088123499,4338079553,17309140419,69107159369,
%U A074526 276040692699,1102999460753,4408508961459,17623571298329
%N A074526 a(n) = 2^n + 3^n + 4^n.
%H A074526 Vincenzo Librandi, <a href="/A074526/b074526.txt">Table of n, a(n) for n = 0..200</a>
%H A074526 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9,-26,24).
%F A074526 From _Mohammad K. Azarian_, Dec 26 2008: (Start)
%F A074526 G.f.: 1/(1-2*x)+1/(1-3*x)+1/(1-4*x).
%F A074526 E.g.f.: exp(2*x)+exp(3*x)+exp(4*x). (End)
%t A074526 Table[2^n + 3^n + 4^n, {n, 0, 23}]
%t A074526 LinearRecurrence[{9,-26,24},{3,9,29},30] (* _Harvey P. Dale_, Jun 14 2022 *)
%o A074526 (Magma) [2^n + 3^n + 4^n: n in [0..25]]; // _Vincenzo Librandi_, Jun 11 2011
%Y A074526 Cf. A001550, A001576, A034513, A001579, A074501 - A074580.
%K A074526 easy,nonn
%O A074526 0,1
%A A074526 _Robert G. Wilson v_, Aug 23 2002