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 A074547 #16 Sep 08 2022 08:45:07
%S A074547 3,12,50,216,962,4392,20450,96696,462722,2234952,10873250,53199576,
%T A074547 261449282,1289406312,6376734050,31605668856,156925904642,
%U A074547 780248462472,3883804162850,19349526496536,96470430052802,481245665067432
%N A074547 a(n) = 3^n + 4^n + 5^n.
%H A074547 Vincenzo Librandi, <a href="/A074547/b074547.txt">Table of n, a(n) for n = 0..200</a>
%H A074547 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (12,-47,60).
%F A074547 From _Mohammad K. Azarian_, Dec 28 2008: (Start)
%F A074547 G.f.: 1/(1-3*x) + 1/(1-4*x) + 1/(1-5*x).
%F A074547 E.g.f.: exp(3*x) + exp(4*x) + exp(5*x). (End)
%F A074547 a(n) = 12*a(n-1) - 47*a(n-2) + 60*a(n-3).
%t A074547 Table[3^n + 4^n + 5^n, {n, 0, 21}]
%o A074547 (Magma) [3^n + 4^n + 5^n: n in [0..30]]; // _Vincenzo Librandi_, Jun 13 2011
%Y A074547 Cf. A001550, A001576, A034513, A001579, A074501 - A074580.
%K A074547 easy,nonn
%O A074547 0,1
%A A074547 _Robert G. Wilson v_, Aug 23 2002