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 A108203 #9 May 16 2019 14:26:04
%S A108203 11,22,33,44,55,66,77,88,99,101,112,123,134,145,156,167,178,189,202,
%T A108203 213,224,235,246,257,268,279,303,314,325,336,347,358,369,404,415,426,
%U A108203 437,448,459,505,516,527,538,549,606,617,628,639,707,718,729,808,819,909,1001
%N A108203 Numbers n put into lexicographical order which are the concatenation of k and the sum of the digits of k.
%e A108203 1 --> 11, 2 --> 22, 3 --> 33, ..., 9 --> 99, 10 --> 101, 11 --> 112, 12 --> 123,
%e A108203 ..., 18 --> 189, 19 --> 1910 (ouch!), 20 --> 202, 21 --> 213, ...
%t A108203 f[n_] := FromDigits[ Join[ IntegerDigits[ n], IntegerDigits[Plus @@ IntegerDigits[ n]] ]]; t = {}; Do[t = Union[AppendTo[t, f[n]]], {n, 10^6}]
%Y A108203 Cf. A062028, A064806. Equals A108773 sorted.
%K A108203 base,nonn
%O A108203 1,1
%A A108203 _Eric Angelini_ and _Robert G. Wilson v_, Jun 15 2005
%E A108203 a(55) from _Rémy Sigrist_, May 16 2019