A119102 Numbers k such that the k-th triangular number contains only digits {1,2,5}.

1, 5, 6, 10, 49, 66, 101, 174, 205, 210, 550, 666, 714, 4806, 5010, 6498, 6666, 10114, 14914, 22410, 66666, 71449, 471701, 495005, 666666, 1500101, 2246130, 3241950, 6666666, 15591825, 17408114, 66666666, 666666666, 1024813373, 1581866714

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119101. See A119034 for a table of cross-references.