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 A074536 #16 Sep 08 2022 08:45:07
%S A074536 3,15,101,801,6833,60105,535601,4799481,43112513,387683145,3487834001,
%T A074536 31385255961,282446317793,2541932945385,22877060906801,
%U A074536 205892205869241,1853024483884673,16677198879666825,150094704016738001
%N A074536 a(n) = 2^n + 4^n + 9^n.
%H A074536 Vincenzo Librandi, <a href="/A074536/b074536.txt">Table of n, a(n) for n = 0..200</a>
%H A074536 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (15,-62,72).
%F A074536 From _Mohammad K. Azarian_, Dec 27 2008: (Start)
%F A074536 G.f.: 1/(1-2*x) + 1/(1-4*x) + 1/(1-9*x).
%F A074536 E.g.f.: exp(2*x) + exp(4*x) + exp(9*x). (End)
%t A074536 Table[2^n + 4^n + 9^n, {n, 0, 20}]
%o A074536 (Magma) [2^n + 4^n + 9^n: n in [0..25]]; // _Vincenzo Librandi_, Jun 11 2011
%Y A074536 Cf. A001550, A001576, A034513, A001579, A074501 - A074580.
%K A074536 easy,nonn
%O A074536 0,1
%A A074536 _Robert G. Wilson v_, Aug 23 2002