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%I #11 Mar 27 2023 03:33:40
%S 55,595,5995,555985,85989999559555,5558888585898885,
%T 898989555999995895,559585958899855598985,988889885885555858595,
%U 85889898559958558998859955,5595888555988988898588558558585,8589985889588895598998885898885995,88988559899558559855895555589855985
%N Triangular numbers composed of digits {5,8,9}.
%C a(14) > 10^40. - _Tyler Busby_, Mar 26 2023
%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr589.html">Tridigital Triangular Numbers</a>.
%F a(n) = A000217(A119229(n)). - _Tyler Busby_, Mar 26 2023
%Y Cf. A000217, A058470, A119229. See A119033 for a table of cross-references.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, May 10 2006
%E a(12)-a(13) from _Tyler Busby_, Mar 26 2023