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 A119177 #12 Mar 31 2023 02:49:24
%S A119177 3,11,36,76,7741188,21305723,4471447856,24343059348,6673334543723,
%T A119177 23094123478785548
%N A119177 Numbers k such that the k-th triangular number contains only digits {2,6,9}.
%H A119177 Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr269.html">Tridigital Triangular Numbers</a>.
%Y A119177 Cf. A000217, A119176. See A119034 for a table of cross-references.
%K A119177 nonn,base,more
%O A119177 1,1
%A A119177 _Giovanni Resta_, May 10 2006
%E A119177 a(10) from _Tyler Busby_, Mar 31 2023