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 A074556 #21 Sep 08 2022 08:45:07
%S A074556 3,17,109,755,5473,40787,309529,2379275,18463393,144315107,1134267049,
%T A074556 8952908795,70896790513,562818102227,4476415458169,35654571422315,
%U A074556 284296129664833,2268726602270147,18115958853570889,144724548978127835
%N A074556 a(n) = 3^n + 6^n + 8^n.
%H A074556 Vincenzo Librandi, <a href="/A074556/b074556.txt">Table of n, a(n) for n = 0..300</a>
%H A074556 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (17,-90,144).
%F A074556 From _Mohammad K. Azarian_, Dec 30 2008: (Start)
%F A074556 G.f.: 1/(1-3*x) + 1/(1-6*x) + 1/(1-8*x).
%F A074556 E.g.f.: e^(3*x) + e^(6*x) + e^(8*x). (End)
%F A074556 a(n) = 17*a(n-1) - 90*a(n-2) + 144*a(n-3); a(0)=3, a(1)=17, a(2)=109. - _Harvey P. Dale_, May 19 2011
%t A074556 Table[3^n + 6^n + 8^n, {n, 0, 20}]
%t A074556 LinearRecurrence[{17,-90,144},{3,17,109},21] (* _Harvey P. Dale_, May 19 2011 *)
%o A074556 (Magma) [3^n + 6^n + 8^n: n in [0..20]]; // _Vincenzo Librandi_, May 20 2011
%Y A074556 Cf. A001550, A001576, A034513, A001579, A074501-A074580.
%K A074556 easy,nonn
%O A074556 0,1
%A A074556 _Robert G. Wilson v_, Aug 23 2002