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 A155641 #16 May 08 2018 18:17:32
%S A155641 1,4,40,388,3472,29644,246520,2019028,16386592,132264604,1063976200,
%T A155641 8541106468,68475336112,548535110764,4391942995480,35153854510708,
%U A155641 281322388820032,2251036874232124,18010583812216360,144096114589527748
%N A155641 8^n-5^n+1^n.
%H A155641 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (14,-53,40).
%F A155641 G.f.: 1/(1-8*x)-1/(1-5*x)+1/(1-x). E.g.f.: e^(8*x)-e^(5*x)+e^x.
%F A155641 a(n)=13*a(n-1)-40*a(n-2)+28 with a(0)=1, a(1)=4 - _Vincenzo Librandi_, Jul 21 2010
%t A155641 Table[8^n-5^n+1^n,{n,0,20}] (* or *) LinearRecurrence[{14,-53,40},{1,4,40},20] (* _Harvey P. Dale_, May 08 2018 *)
%o A155641 (PARI) a(n)=8^n-5^n+1 \\ _Charles R Greathouse IV_, Jun 11 2015
%Y A155641 Cf. A155624, A155625, A155626, A155627, A155628, A155629, A155630, A155631, A155632, A155633, A155634, A155635, A155636, A155637, A155638, A155639, A155640.
%K A155641 nonn,easy
%O A155641 0,2
%A A155641 _Mohammad K. Azarian_, Jan 30 2009