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 A155601 #26 Mar 10 2022 05:21:37
%S A155601 1,9,97,993,9985,99969,999937,9999873,99999745,999999489,9999998977,
%T A155601 99999997953,999999995905,9999999991809,99999999983617,
%U A155601 999999999967233,9999999999934465,99999999999868929,999999999999737857,9999999999999475713,99999999999998951425
%N A155601 a(n) = 10^n - 2^n + 1^n.
%H A155601 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (13,-32,20).
%F A155601 G.f.: 1/(1-10*x)-1/(1-2*x)+1/(1-x).
%F A155601 E.g.f.: e^(10*x)-e^(2*x)+e^x.
%F A155601 a(n) = 12*a(n-1)-20*a(n-2)+9 with a(0)=1, a(1)=9. - _Vincenzo Librandi_, Jul 21 2010
%F A155601 a(n) = A060458(n)+1. - _R. J. Mathar_, Mar 10 2022
%t A155601 Table[10^n-2^n+1,{n,0,20}] (* or *) LinearRecurrence[{13,-32,20},{1,9,97},20] (* _Harvey P. Dale_, Jan 13 2022 *)
%o A155601 (PARI) a(n)=10^n-2^n+1 \\ _Charles R Greathouse IV_, Sep 24 2015
%Y A155601 Cf. A074501, A020515, A155588, A155590, A155592, A155593, A155594, A155596, A155597, A155598, A155599, A155600.
%K A155601 nonn,easy
%O A155601 0,2
%A A155601 _Mohammad K. Azarian_, Jan 25 2009