A119147 Numbers k such that the k-th triangular number contains only digits {1,7,8}.

1, 12, 18, 58, 132, 153, 1332, 1541, 6018, 11981, 13332, 40278, 124753, 133332, 603121, 1332507, 1333332, 13332507, 13333332, 19072906, 133332507, 133333332, 485569333, 486040907, 612880278, 1247972658, 1333332507

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• G. Resta, Tridigital Triangular Numbers

Crossrefs

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