The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #12 Mar 29 2023 15:37:56
%S 3,55,595,5995,33533955,5939355555,9993335593335,535555935535935,
%T 599593353353393939939955,595993553593935939553359535599399555
%N Triangular numbers composed of digits {3,5,9}.
%C a(11) > 10^39. - _Tyler Busby_, Mar 29 2023
%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr359.html">Tridigital Triangular Numbers</a>.
%F a(n) = A000217(A119193(n)).
%Y Cf. A000217, A119193. See A119033 for a table of cross-references.
%K nonn,base,more
%O 1,1
%A _Giovanni Resta_, May 10 2006
%E a(10) from _Max Alekseyev_, May 21 2011