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 A074541 #16 Sep 08 2022 08:45:07
%S A074541 3,15,89,567,3713,24615,164369,1103607,7444673,50431815,342942449,
%T A074541 2340125847,16018073633,109949712615,756587253329,5217746527287,
%U A074541 36054040542593,249557173563015,1729973554841009,12008254925907927
%N A074541 a(n) = 2^n + 6^n + 7^n.
%H A074541 Vincenzo Librandi, <a href="/A074541/b074541.txt">Table of n, a(n) for n = 0..200</a>
%H A074541 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (15,-68,84).
%F A074541 From _Mohammad K. Azarian_, Dec 27 2008: (Start)
%F A074541 G.f.: 1/(1-2*x) + 1/(1-6*x) + 1/(1-7*x).
%F A074541 E.g.f.: exp(2*x) + exp(6*x) + exp(7*x). (End)
%t A074541 Table[2^n + 6^n + 7^n, {n, 0, 20}]
%o A074541 (Magma) [2^n + 6^n + 7^n: n in [0..25]]; // _Vincenzo Librandi_, Jun 11 2011
%Y A074541 Cf. A001550, A001576, A034513, A001579, A074501 - A074580.
%K A074541 easy,nonn
%O A074541 0,1
%A A074541 _Robert G. Wilson v_, Aug 23 2002