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%I #13 Mar 29 2023 17:19:55
%S 6,66,666,476776,764466,4646676,464774774646,
%T 667474767766464747666467446,7666777767444444644744476476,
%U 44774674766666676747766477446
%N Triangular numbers composed of digits {4,6,7}.
%C a(11) > 10^40. - _Tyler Busby_, Mar 29 2023
%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr467.html">Tridigital Triangular Numbers</a>.
%F a(n) = A000217(A119211(n)). - _Michel Marcus_, Mar 27 2023
%Y Cf. A000217, A053957, A119211. See A119033 for a table of cross-references.
%K nonn,base,more
%O 1,1
%A _Giovanni Resta_, May 10 2006