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 A119054 #15 Sep 08 2022 08:45:25
%S A119054 3,11,36,363,1095,3640,72396,2097628,1119484011,11489670148,
%T A119054 200329741476,666663663636,6666633636651,11508483829424,
%U A119054 203306006810436
%N A119054 Numbers k such that the k-th triangular number contains only digits {0,2,6}.
%C A119054 No other terms below 1.4*10^20. - _Max Alekseyev_, Aug 26 2013
%H A119054 G. Resta, <a href="http://www.numbersaplenty.com/tr/tr026.html">Tridigital Triangular Numbers</a>
%t A119054 Select[Range[2 10^7], Complement[IntegerDigits[Binomial[# + 1, 2]], {0, 2, 6}] == {} &] (* _Vincenzo Librandi_, Dec 25 2015 *)
%o A119054 (Magma) [n: n in [1..4*10^6] | Set(Intseq(Binomial(n+1, 2))) subset [0, 2, 6]]; // _Vincenzo Librandi_, Dec 25 2015
%Y A119054 Cf. A000217, A119053. See A119034 for a table of cross-references.
%K A119054 nonn,base,more
%O A119054 1,1
%A A119054 _Giovanni Resta_, May 10 2006