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 A119045 #15 Mar 12 2023 08:48:05
%S A119045 1,10,1081,8001,10011,81810,108811,1188111,8018010,8801110,10888111,
%T A119045 80118811,88000011,800180010,881811010,1088881111,10808101800,
%U A119045 80001800010,81108010180,108888811111,810008010801,880818181011,888000000111,8000018000010,10888888111111
%N A119045 Triangular numbers composed of digits {0,1,8}.
%H A119045 Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr018.html">Tridigital Triangular Numbers</a>
%F A119045 a(n) = A000217(A119046(n)). - _Michel Marcus_, Mar 11 2023
%t A119045 Rest[Select[FromDigits/@Tuples[{0,1,8},12],OddQ[Sqrt[8#+1]]&]] (* or *) Select[Accumulate[Range[1328*10^3]],SubsetQ[{0,1,8}, IntegerDigits[ #]]&](* _Harvey P. Dale_, May 06 2019 *)
%Y A119045 Cf. A000217, A058422, A119046. See A119033 for a table of cross-references.
%K A119045 nonn,base
%O A119045 1,2
%A A119045 _Giovanni Resta_, May 10 2006
%E A119045 a(23)-a(25) from _Tyler Busby_, Mar 11 2023