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 A155670 #18 Jul 22 2025 06:19:21
%S A155670 1,19,201,2059,21201,220099,2303001,24270139,257405601,2745368179,
%T A155670 29424209001,316692730219,3420857913201,37064577972259,
%U A155670 402626626038201,4383139301510299,47802750052424001,522124210198960339
%N A155670 11^n+9^n-1^n.
%H A155670 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (21,-119,99).
%F A155670 G.f.: 1/(1-11*x)+1/(1-9*x)-1/(1-x). E.g.f.: e^(11*x)+e^(9*x)-e^x.
%F A155670 a(n)=20*a(n-1)-99*a(n-2)-80 with a(0)=1, a(1)=19 - _Vincenzo Librandi_, Jul 21 2010
%t A155670 Table[11^n+9^n-1^n, {n,0,30}] (* _Harvey P. Dale_, Mar 26 2011 *)
%o A155670 (PARI) a(n)=11^n+9^n-1^n \\ _Charles R Greathouse IV_, Oct 16 2015
%Y A155670 A155646, A155647, A155648, A155649, A155650, A155651, A155652, A155653, A155654, A155655, A155656, A155657, A155658, A155659, A155660, A155661, A155662, A155663, A155664, A155665, A155666, A155667, A155668, A155669
%K A155670 nonn,easy
%O A155670 0,2
%A A155670 _Mohammad K. Azarian_, Feb 01 2009