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 A155613 #15 Oct 07 2015 11:32:34
%S A155613 1,6,56,486,4016,32526,261416,2094966,16770656,134198046,1073682776,
%T A155613 8589757446,68718945296,549754219566,4398041728136,35184357739926,
%U A155613 281474933663936,2251799684545086,18014398122061496,144115186913594406
%N A155613 8^n - 3^n + 1.
%H A155613 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (12,-35,24).
%F A155613 G.f.: 1/(1-8*x)-1/(1-3*x)+1/(1-x).
%F A155613 E.g.f.: e^(8*x)-e^(3*x)+e^x.
%F A155613 a(n) = 11*a(n-1)-24*a(n-2)+14 with a(0)=1, a(1)=6. - _Vincenzo Librandi_, Jul 21 2010
%t A155613 Table[8^n-3^n+1,{n,0,20}] (* or *) LinearRecurrence[{12,-35,24},{1,6,56},20] (* _Harvey P. Dale_, Mar 12 2014 *)
%o A155613 (PARI) a(n)=8^n-3^n+1 \\ _Charles R Greathouse IV_, Oct 07 2015
%Y A155613 Cf. A155596, A155597, A155598, A155599, A155600, A155601, A155602, A155603, A155604, A155605, A155606, A155607, A155608, A155609, A155610, A155611, A155612.
%K A155613 nonn,easy
%O A155613 0,2
%A A155613 _Mohammad K. Azarian_, Jan 26 2009