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 A171510 #25 Jan 03 2024 23:47:50
%S A171510 2,1,12,121,1222,12341,124632,1258661,12711242,128371081,1296422052,
%T A171510 13092591601,132222338062,1335315972221,13485382060272,
%U A171510 136189136574941,1375376747809682,13889956614671761,140274942894527292,1416639385559944681,14306668798493974102
%N A171510 a(n) = 10*a(n-1) + a(n-2), with a(1)=2 and a(2)=1.
%H A171510 Colin Barker, <a href="/A171510/b171510.txt">Table of n, a(n) for n = 1..997</a>
%H A171510 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (10,1).
%F A171510 G.f.: x*(19*x-2) / (x^2+10*x-1). - _Colin Barker_, Oct 02 2015
%t A171510 RecurrenceTable[{a[n] == 10 a[n - 1] + a[n - 2], a[1] == 2, a[2] == 1}, a, {n, 1, 21}] (* or *) LinearRecurrence[{10, 1}, {2, 1}, 21] (* _Michael De Vlieger_, Oct 02 2015 *)
%o A171510 (PARI) Vec(x*(19*x-2)/(x^2+10*x-1) + O(x^40)) \\ _Colin Barker_, Oct 02 2015
%Y A171510 Cf. A015456, A065941.
%K A171510 nonn,easy
%O A171510 1,1
%A A171510 _Mark Dols_, Dec 10 2009