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 A119157 #15 Aug 04 2025 02:31:47
%S A119157 2,7,87,1287,881287,21158087,25800318712,7535029241912
%N A119157 Numbers k such that the k-th triangular number contains only digits {2,3,8}.
%C A119157 Next term exceeds 4.4*10^20.
%H A119157 G. Resta, <a href="http://www.numbersaplenty.com/tr/tr238.html">Tridigital Triangular Numbers</a>
%Y A119157 Cf. A000217, A119156. See A119034 for a table of cross-references.
%K A119157 nonn,base,more
%O A119157 1,1
%A A119157 _Giovanni Resta_, May 10 2006
%E A119157 Lower bound for the next term updated by _Max Alekseyev_, May 21 2009, Mar 05 2023