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 A119169 #12 Mar 31 2023 02:28:31
%S A119169 7,10,32,714,1025,1287,6712,10849,13285,23885,711129,22595807,
%T A119169 22619825,40641912,715385610,33343322745,332431301950,23785828913825,
%U A119169 32503094884196145
%N A119169 Numbers k such that the k-th triangular number contains only digits {2,5,8}.
%H A119169 Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr258.html">Tridigital Triangular Numbers</a>.
%Y A119169 Cf. A000217, A119168. See A119034 for a table of cross-references.
%K A119169 nonn,base,more
%O A119169 1,1
%A A119169 _Giovanni Resta_, May 10 2006
%E A119169 a(19) from _Tyler Busby_, Mar 31 2023