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 A074540 #17 Sep 08 2022 08:45:07
%S A074540 3,16,110,862,7202,62206,547130,4861222,43437602,389374126,3496551050,
%T A074540 31429889782,282673681202,2543086539646,22882895986970,
%U A074540 205921649705542,1853172776808002,16677944639250766,150098449994526890,1350870791159844502,12157760826489618002
%N A074540 a(n) = 2^n + 5^n + 9^n.
%H A074540 Vincenzo Librandi, <a href="/A074540/b074540.txt">Table of n, a(n) for n = 0..200</a>
%H A074540 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (16,-73,90).
%F A074540 From _Mohammad K. Azarian_, Dec 27 2008: (Start)
%F A074540 G.f.: 1/(1-2*x) + 1/(1-5*x) + 1/(1-9*x).
%F A074540 E.g.f.: exp(2*x) + exp(5*x) + exp(9*x). (End)
%F A074540 a(n) = 16*a(n-1) - 73*a(n-2) + 90*a(n-3) for n > 2. - _Wesley Ivan Hurt_, Oct 06 2017
%p A074540 A074540:=n->2^n + 5^n + 9^n: seq(A074540(n), n=0..30); # _Wesley Ivan Hurt_, Oct 06 2017
%t A074540 Table[2^n + 5^n + 9^n, {n, 0, 20}]
%o A074540 (Magma) [2^n + 5^n + 9^n: n in [0..25]]; // _Vincenzo Librandi_, Jun 11 2011
%Y A074540 Cf. A001550, A001576, A001579, A034513, A074501 - A074580.
%K A074540 easy,nonn
%O A074540 0,1
%A A074540 _Robert G. Wilson v_, Aug 23 2002