A119131 Numbers k such that the k-th triangular number contains only digits {1,4,9}.

1, 13, 313, 538, 13741, 43386, 48886, 991886, 141415133, 2880781113, 4721227413, 19567549258, 538423521386, 137473211871979931561

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Links

• G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119130. See A119034 for a table of cross-references.

Extensions

a(14) from Max Alekseyev, Aug 15 2013