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 A136613 #11 May 06 2025 22:53:13
%S A136613 0,11,22,33,44,55,66,77,88,99,110,211,312,413,514,615,716,817,918,
%T A136613 1019,220,321,422,523,624,725,826,927,1028,1129,330,431,532,633,734,
%U A136613 835,936,1037,1138,1239,440,541,642,743,844,945,1046,1147,1248,1349,550,651,752
%N A136613 Concatenation of (sum of digits of n) and n.
%H A136613 Reinhard Zumkeller, <a href="/A136613/b136613.txt">Table of n, a(n) for n = 0..10000</a>
%F A136613 A136614(n) = A007953(a(n)) = A007953(A108773(n)).
%t A136613 a[n_]:=FromDigits[Join[{DigitSum[n]},IntegerDigits[n]]] (* _James C. McMahon_, May 06 2025 *)
%Y A136613 Cf. A007953, A108773, A136614.
%K A136613 nonn,base,look
%O A136613 0,2
%A A136613 _Reinhard Zumkeller_, Jan 13 2008