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%I #13 Mar 29 2023 19:56:46
%S 55,595,5995,7779577597795,9775779559755,57575799959759975575,
%T 77777755779995957575,7577959575775997959995995979795
%N Triangular numbers composed of digits {5,7,9}.
%C a(9) > 10^40. - _Tyler Busby_, Mar 29 2023
%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr579.html">Tridigital Triangular Numbers</a>.
%F a(n) = A000217(A119227(n)). - _Michel Marcus_, Mar 27 2023
%Y Cf. A000217, A119227. See A119033 for a table of cross-references.
%K nonn,base,more
%O 1,1
%A _Giovanni Resta_, May 10 2006