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 A016195 #18 Jun 29 2023 15:32:22 %S A016195 0,1,21,331,4641,61051,771561,9487171,114358881,1357947691, %T A016195 15937424601,185311670611,2138428376721,24522712143931, %U A016195 279749833583241,3177248169415651,35949729863572161,405447028499293771 %N A016195 a(n) = 11^n - 10^n. %H A016195 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (21, -110). %F A016195 G.f.: x/((1-10x)(1-11x)). %F A016195 E.g.f.: e^(11*x) - e^(10*x). - _Mohammad K. Azarian_, Jan 14 2009 %F A016195 a(n) = 11*a(n-1) + 10^(n-1), a(0)=0. - _Vincenzo Librandi_, Feb 09 2011 %F A016195 a(n) = 21*a(n-1) - 110*a(n-2), a(0)=0, a(1)=1. - _Vincenzo Librandi_, Feb 09 2011 %t A016195 f[n_]:=11^n-10^n;f[Range[0,40]] (* _Vladimir Joseph Stephan Orlovsky_, Feb 14 2011 *) %K A016195 nonn %O A016195 0,3 %A A016195 _N. J. A. Sloane_