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 A119185 #7 Jul 13 2021 21:04:20
%S A119185 2,3,8,11,36,816,85611,364243,81775868,817858956,832639591,
%T A119185 85374871556,94304439591,1152678139331,29551086049868,112573208752763,
%U A119185 855959656346411,966058450039783,1151819988918983
%N A119185 Numbers k such that the k-th triangular number contains only digits {3,4,6}.
%C A119185 Next term exceeds 1.4*10^16.
%H A119185 G. Resta, <a href="http://www.numbersaplenty.com/tr/tr346.html">Tridigital Triangular Numbers</a>
%Y A119185 Cf. A000217, A119184. See A119034 for a table of cross-references.
%K A119185 nonn,base,more
%O A119185 1,1
%A A119185 _Giovanni Resta_, May 10 2006