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 A347520 #19 Sep 04 2021 20:03:38
%S A347520 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,21,22,23,24,25,26,
%T A347520 27,28,29,210,32,33,34,35,36,37,38,39,310,311,43,44,45,46,47,48,49,
%U A347520 410,411,412,54,55,56,57,58,59
%N A347520 A053392 with duplicates removed.
%H A347520 Dana G. Korssjoen, Biyao Li, Stefan Steinerberger, Raghavendra Tripathi, and Ruimin Zhang, <a href="https://arxiv.org/abs/2012.04625">Finding structure in sequences of real numbers via graph theory: a problem list</a>, arXiv:2012.04625 [math.CO], 2020.
%t A347520 a[n_] := Total /@ Transpose[{Most[id = IntegerDigits[n]], Rest[id]}] //
%t A347520 IntegerDigits // Flatten // FromDigits; DeleteDuplicates[Table[a[n], {n, 0, 1000}]]
%o A347520 (Python) # uses A053392
%o A347520 from collections import OrderedDict
%o A347520 def afiltern(terms):
%o A347520 return list(OrderedDict.fromkeys(A053392(k) for k in range(terms)))
%o A347520 print(afiltern(179)) # _Michael S. Branicky_, Sep 04 2021
%Y A347520 Cf. A053392.
%K A347520 nonn
%O A347520 0,3
%A A347520 _Stefan Steinerberger_, Sep 04 2021