%I #11 Mar 31 2023 03:20:29

%S 3,10,11,34,36,105,109,114,3363,13834,438109,1383471,3622034,10954411,

%T 11537388,33336636,105517363,141114114,3333366765,3333333366663363,

%U 333645229535671903

%N Numbers k such that the k-th triangular number contains only digits {5,6,9}.

%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr569.html">Tridigital Triangular Numbers</a>.

%Y Cf. A000217, A119222. See A119034 for a table of cross-references.

%K nonn,base,more

%O 1,1

%A _Giovanni Resta_, May 10 2006

%E a(21) from _Tyler Busby_, Mar 31 2023