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Triangular numbers composed of digits {1,3,8}.
2

%I #10 Mar 29 2023 05:02:12

%S 1,3,88831,1188111,38311881,11313313831,83388881331381,

%T 881388838113181838838811,8138133831331381318318881,

%U 183113183318838311383311313311,133831381813113188111133181833111,31188113313888818318833183383131131

%N Triangular numbers composed of digits {1,3,8}.

%C No other terms below 10^41. - _Tyler Busby_, Mar 28 2023

%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr138.html">Tridigital Triangular Numbers</a>.

%F a(n) = A000217(A119120(n)). - _Tyler Busby_, Mar 28 2023

%Y Cf. A000217, A053895, A119120. See A119033 for a table of cross-references.

%K nonn,base

%O 1,2

%A _Giovanni Resta_, May 10 2006

%E Two more terms from _Max Alekseyev_, May 12 2009