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 A172175 #21 Mar 04 2024 01:13:29
%S A172175 1,111,12211,1343211,147753211,16252853211,1787813853211,
%T A172175 196659523853211,21632547623853211,2379580238623853211,
%U A172175 261753826248623853211,28792920887348623853211,3167221297608348623853211,348394342736918348623853211,38323377701061018348623853211
%N A172175 a(n) = 110*a(n-1) + 1.
%C A172175 Sum of pairs of integers given in A162849. Sum of digits give A000225.
%H A172175 Colin Barker, <a href="/A172175/b172175.txt">Table of n, a(n) for n = 1..490</a>
%H A172175 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (111,-110).
%F A172175 From _Colin Barker_, Oct 02 2015: (Start)
%F A172175 a(n) = 111*a(n-1) - 110*a(n-2) for n>2.
%F A172175 G.f.: 1 / ((1-x)*(1-110*x)). (End)
%t A172175 a = {1}; Do[AppendTo[a, 110 a[[n-1]] + 1], {n, 2, 15}]; a (* _Michael De Vlieger_, Oct 02 2015 *)
%o A172175 (PARI) Vec(1/((x-1)*(110*x-1)) + O(x^30)) \\ _Colin Barker_, Oct 02 2015
%o A172175 (SageMath) [((110)^n -1)/109 for n in (1..50)] # _G. C. Greubel_, Apr 26 2022
%Y A172175 Cf. A000225, A162849, A165155.
%K A172175 nonn,easy
%O A172175 1,2
%A A172175 _Mark Dols_, Jan 28 2010