A119139 Numbers k such that the k-th triangular number contains only digits {1,5,9}.

1, 5, 10, 13, 34, 101, 109, 138, 1738, 10114, 19794, 1011090, 1019010, 1054130, 1091010, 34406858, 178858133, 565606858, 4289521091010, 55841058721258

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Comments

Next term exceeds 1.4*10^16.

Links

• G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119138. See A119034 for a table of cross-references.