A119147 - OEIS

%I #8 Jul 13 2021 07:26:38

%S 1,12,18,58,132,153,1332,1541,6018,11981,13332,40278,124753,133332,

%T 603121,1332507,1333332,13332507,13333332,19072906,133332507,

%U 133333332,485569333,486040907,612880278,1247972658,1333332507

%N Numbers k such that the k-th triangular number contains only digits {1,7,8}.

%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr178.html">Tridigital Triangular Numbers</a>

%Y Cf. A000217, A119146. See A119034 for a table of cross-references.

%K nonn,base

%O 1,2

%A _Giovanni Resta_, May 10 2006