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 A371031 #35 Mar 31 2024 14:03:13
%S A371031 9,17,170,323,3230,6137,61370,116603,1166030,2215457
%N A371031 Number of distinct integers resulting from adding an n-digit non-multiple of 10 and its reverse.
%F A371031 For n > 1, empirically a(n+1) = 10 a(n) if n even, 19 a(n) / 10 if n odd, and thus a(n+2) = 19 a(n). - _Michael S. Branicky_, Mar 31 2024
%e A371031 For n=2 there are 81 2-digit numbers not ending with 0: {11, 12, 13, ..., 99}. There are 17 distinct results when adding each of these to their reversal: {22, 33, 44, 55, 66, 77, 88, 99, 110, 121, 132, 143, 154, 165, 176, 187, 198}. Therefore a(2) = 17.
%t A371031 A371031[n_] :=
%t A371031 Module[{nn, ss},
%t A371031 nn = Select[Range[If[n == 1, 1, 10^(n - 1) + 1], 10^n - 1], Mod[#, 10] > 0 &];
%t A371031 ss = Map[# + FromDigits[Reverse[IntegerDigits[#]]] &, nn];
%t A371031 Return[CountDistinct[ss]]
%t A371031 ];
%t A371031 Map[A371031[#]&, Range[7]]
%Y A371031 Cf. A056964, A067251, A358985.
%K A371031 nonn,base,more
%O A371031 1,1
%A A371031 _César Eliud Lozada_, Mar 08 2024
%E A371031 a(9)-a(10) from _Michael S. Branicky_, Mar 30 2024