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 A082215 #45 Aug 29 2021 02:05:29
%S A082215 1,121,1213121,121312141213121,1213121412131215121312141213121,
%T A082215 121312141213121512131214121312161213121412131215121312141213121,
%U A082215 1213121412131215121312141213121612131214121312151213121412131217121312141213121512131214121312161213121412131215121312141213121
%N A082215 Concatenation of terms of A018238.
%C A082215 Also called Zimin words.
%C A082215 a(n) is a palindrome for n<10; it is debatable whether a(n) can be called a Zimin word for n>=10 (see the Comments in A018238). - _Danny Rorabaugh_, Sep 26 2015
%H A082215 J. Cooper and D. Rorabaugh, <a href="http://arxiv.org/abs/1409.3080">Bounds on Zimin Word Avoidance</a>, arXiv:1409.3080 [math.CO], 2014; Congressus Numerantium, 222 (2014), 87-95.
%H A082215 L. J. Cummings and M. Mays, <a href="https://doi.org/10.37236/1571">A one-sided Zimin construction</a>, Electron. J. Combin. 8 (2001), #R27.
%H A082215 A. I. Zimin, <a href="http://mi.mathnet.ru/eng/msb2889">Blocking sets of terms</a>, Math. USSR Sbornik, 47 (1984), No. 2, 353-364.
%F A082215 The Zimin words are defined here by Z_1 = 1, Z_n = Z_{n-1}nZ_{n-1}. - _Dmitry Kamenetsky_, Sep 30 2006
%t A082215 a = {1}; Do[w = IntegerDigits@ a[[n - 1]]; AppendTo[a, FromDigits@ Join[w, IntegerDigits@ n, w]], {n, 2, 7}]; a (* _Michael De Vlieger_, Sep 26 2015 *)
%Y A082215 Cf. A018238, A123121, A033564.
%Y A082215 See A001511 for another representation of this sequence of digits.
%K A082215 base,nonn
%O A082215 1,2
%A A082215 _Amarnath Murthy_, Apr 08 2003
%E A082215 More terms from _Joshua Zucker_, May 08 2006
%E A082215 "Palindromes" replaced with "Numbers" in sequence name by _Danny Rorabaugh_, Sep 26 2015
%E A082215 Shorter name by _Joerg Arndt_, Aug 28 2021