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%I #12 Apr 06 2023 20:07:10
%S 45,55,25425,255255,22542255,244525555,2245524452445,2445254445525,
%T 5255545252454245,444222245455224445,4544525455555255444225,
%U 5554545454254522254255544522452525245
%N Triangular numbers composed of digits {2,4,5}.
%C a(13) > 10^40.
%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr245.html">Tridigital Triangular Numbers</a>.
%F a(n) = A000217(A119159(n)).
%Y Cf. A000217, A031152, A119159. See A119033 for a table of cross-references.
%K nonn,base,more
%O 1,1
%A _Giovanni Resta_, May 10 2006
%E a(12) from _Max Alekseyev_, Aug 19 2013