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 A119162 #12 Apr 06 2023 21:41:50
%S A119162 28,48828,828828,842288428828,24884484228828,28284882828828,
%T A119162 2842448222228428828
%N A119162 Triangular numbers composed of digits {2,4,8}.
%C A119162 a(8) > 10^40. - _Tyler Busby_, Mar 29 2023
%H A119162 Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr248.html">Tridigital Triangular Numbers</a>.
%F A119162 a(n) = A000217(A119163(n)). - _Tyler Busby_, Mar 29 2023
%Y A119162 Cf. A000217, A027678, A119163. See A119033 for a table of cross-references.
%K A119162 nonn,base,more
%O A119162 1,1
%A A119162 _Giovanni Resta_, May 10 2006