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 A119056 #8 Jul 13 2021 01:21:05
%S A119056 7,40,64,400,632,1287,4000,40000,126712,209775,400000,646232,663367,
%T A119056 4000000,40000000,75897600,213645607,400000000,4000000000,12713841912,
%U A119056 40000000000,400000000000,749506541784,4000000000000,20397451214712
%N A119056 Numbers k such that the k-th triangular number contains only digits {0,2,8}.
%H A119056 G. Resta, <a href="http://www.numbersaplenty.com/tr/tr028.html">Tridigital Triangular Numbers</a>
%Y A119056 Cf. A000217, A119055. See A119034 for a table of cross-references.
%K A119056 nonn,base
%O A119056 1,1
%A A119056 _Giovanni Resta_, May 10 2006