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 A155608 #17 Sep 28 2015 10:51:54
%S A155608 1,12,108,1026,10080,100242,1000728,10002186,100006560,1000019682,
%T A155608 10000059048,100000177146,1000000531440,10000001594322,
%U A155608 100000004782968,1000000014348906,10000000043046720,100000000129140162
%N A155608 10^n + 3^n - 1.
%H A155608 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (14,-43,30).
%F A155608 G.f.: 1/(1-10*x)+1/(1-3*x)-1/(1-x).
%F A155608 E.g.f.: e^(10*x)+e^(3*x)-e^x.
%F A155608 a(n) = 13*a(n-1)-30*a(n-2)-18 with a(0)=1, a(1)=12. - _Vincenzo Librandi_, Jul 21 2010
%p A155608 A155608:=n->10^n + 3^n - 1; seq(A155608(n), n=0..30); # _Wesley Ivan Hurt_, Apr 02 2014
%t A155608 Table[10^n + 3^n - 1, {n, 0, 30}] (* _Wesley Ivan Hurt_, Apr 02 2014 *)
%o A155608 (PARI) a(n)=10^n+3^n-1 \\ _Charles R Greathouse IV_, Sep 28 2015
%Y A155608 Cf. A155596, A155597, A155598, A155599, A155600, A155601, A155602, A155603, A155604, A155605, A155606, A155607.
%K A155608 nonn,easy
%O A155608 0,2
%A A155608 _Mohammad K. Azarian_, Jan 25 2009