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Numbers k such that the k-th triangular number contains only digits {1,5,8}.
2

%I #8 Jul 13 2021 07:28:32

%S 1,5,10,101,130,1078,1330,1541,4730,10114,12773,13330,41269,133330,

%T 1333330,13333330,133333330,1333333330,3430798394,5506103010,

%U 13333333330,108245601470,133333333330,1305029950270,1333333333330

%N Numbers k such that the k-th triangular number contains only digits {1,5,8}.

%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr158.html">Tridigital Triangular Numbers</a>

%Y Cf. A000217, A119136. See A119034 for a table of cross-references.

%K nonn,base

%O 1,2

%A _Giovanni Resta_, May 10 2006